Device for active overvoltage protection

Abstract

The invention relates to a device for active overvoltage protection, and particularly discloses a circuit protection device. The circuit protection device includes an active energy absorber coupled between two power lines in a power distribution system and configured to selectively conduct a fault current in response to an overvoltage condition. The active energy absorber comprises: an overvoltage protection module, wherein the overvoltage protection module comprises two thyristors which are in anti-parallel connection with each other; and the rheostat is connected with the overvoltage protection module to form a series circuit. The series circuit including the varistor and the overvoltage protection module is connected between the power lines.

Description

[0001] This application is a divisional application of the invention patent application with application number 202210314788.8, application date December 25, 2017, and invention name “Device for active overvoltage protection”. Technical Field

[0002] The present invention relates to circuit protection devices, and more particularly to overvoltage protection devices and methods. Background Art

[0003] Excess voltage or current is often applied across the service lines that deliver power to residences and commercial and industrial facilities. For example, such excess voltage or current spikes (transient overvoltage and surge current) may be caused by lightning strikes. The following facilities are particularly affected by such events: telecommunications dispatch centers, hospitals, and other facilities where equipment damage caused by overvoltage and / or current surges and the resulting downtime can be very costly.

[0004] Typically, surge protection devices (SPDs) are used to protect sensitive electronic equipment from transient overvoltages and surge currents. For example, simply refer to Figure 1 , Figure 1 It is a system including conventional overvoltage and surge protection. The overvoltage protection device 10 can be installed at the power input of the device 50 to be protected, and the device 50 to be protected is usually protected from overcurrent when it fails. The typical failure mode of SPD is short circuit. The overcurrent protection commonly used is a combination of an internal thermal cut-off to protect the device from overheating due to increased leakage current and an external fuse to protect the device from higher fault currents. Different SPD technologies can avoid the use of internal thermal cut-offs because they change their operating mode to low ohm resistance when a fault occurs. In this way, the device can withstand considerable short-circuit currents. In this regard, an internal thermal cut-off may not be required in operation. In addition, some embodiments that exhibit even higher short-circuit current tolerance can also be protected only by the main circuit breaker of the device without the need for dedicated shunt fuses.

[0005] Now simply refer to Figure 2 , Figure 2 6 is a block diagram of a system including common surge protection. As illustrated, the three-phase line can be connected to one or more transformers 66 and supply electrical energy to one or more transformers 66, which can in turn supply three-phase electrical power to the main circuit breaker 68. Three-phase electrical power can be provided to one or more distribution boards 62. As illustrated, the three voltage lines of the three-phase electrical power can be designated as L1, L2 and L3, and the neutral line can be designated as N. In some embodiments, the neutral line N can be conductively connected to ground.

[0006] Some embodiments include a surge protection device (SPD) 104. As illustrated, each SPD 104 can be connected between a corresponding one of L1, L2, and L3 and the neutral line (N). The SPD 104 can protect other devices in the device, such as a distribution board, etc. In addition, the SPD can be used to protect all devices in the case of a long-lasting overvoltage. However, this situation will force the SPD to conduct a limited current for a long period of time, which will cause the SPD to overheat and possibly fail (depending on the energy tolerance that the SPD can absorb and the level and duration of the overvoltage situation). In this example, the typical operating voltage of the SPD 104 can be about 400V (for a 690V LL system). In this regard, the SPD 104 will each behave as an insulator and therefore will not conduct current during normal operating conditions. In some embodiments, the operating voltage of the SPD 104 is sufficiently higher than the normal line-to-neutral voltage to ensure that the SPD 104 will continue to behave as an insulator even if the system voltage increases due to an overvoltage condition that may occur due to loss of neutral or other power system problems.

[0007] If a surge current occurs in, for example, L1, the protection of the power system load device may require providing a current path to the ground for the excess current of the surge current. The surge current may generate a transient overvoltage between L1 and N. Since the transient overvoltage significantly exceeds the operating voltage of the SPD 104, the SPD 104 will become conductive, allowing the excess current to flow from L1 to the neutral line N through the SPD 104. Once the surge current has been conducted to N, the overvoltage condition will end and the SPD 104 may become non-conductive again. However, in some cases, one or more SPDs 104 may begin to allow leakage current to be conducted even at a voltage lower than the operating voltage of the SPD 104. This may occur when the SPD is degraded.

[0008] As provided above, devices for protecting equipment from excess voltage or current spikes (transient overvoltage and surge current) may include products such as energy absorbers, which may be based on varistors, including, for example, metal oxide varistors (MOVs) and / or silicon carbide varistors, and which may not have a safe end-of-life operating mode. In addition, such devices may not provide protection at voltage levels close to the operating voltage of the device. Further, surge protection device designs may not provide protection at voltage levels close to the nominal system voltage and may not be designed to absorb as much energy as the energy absorber. Combinations of varistors and thyristors may not have safe failure modes and may not be able to protect against surge currents and transient overvoltages in the absence of an external SPD. Therefore, what is desired is a surge protection product that provides a low voltage protection level and provides protection against transient overvoltages (TOVs) implemented in a fail-safe design. Summary of the invention

[0009] Some embodiments of the present invention relate to a circuit protection device, which includes: an active energy absorber, which is connected between a neutral line and / or two of a plurality of phase lines in a power distribution system and is configured to selectively conduct a fault current in response to an overvoltage condition.

[0010] In some embodiments, the active energy absorber includes: an overvoltage protection module, the overvoltage protection module including two thyristors connected in anti-parallel to each other; and a metal oxide varistor (MOV), the MOV and the overvoltage protection module are connected in series. Some embodiments provide that the series circuit including the MOV and the overvoltage protection module is connected between any two of the neutral line and / or the phase line.

[0011] Some embodiments provide that: the active energy absorber further comprises an inductor, the inductor being connected in series with a series circuit comprising the MOV and the overvoltage protection module. In some embodiments, the MOV comprises a plurality of MOVs connected in parallel with each other.

[0012] Some embodiments include a surge protection device connected between any two phase conductors and / or a neutral conductor and configured to protect equipment connected thereto during an overvoltage condition by conducting a limited amount of current corresponding to the overvoltage condition.

[0013] Some embodiments include a trigger circuit connected to any two phase lines and / or a neutral line and the overvoltage protection module, and configured to provide a control signal to the overvoltage protection module in response to detecting a transient overvoltage condition across any two phase lines and / or a neutral line. In some embodiments, the trigger circuit includes: a comparison circuit configured to receive a voltage level signal and a voltage reference signal, and output an overvoltage trigger signal in response to the voltage level signal exceeding the voltage reference signal; and a gate-level trigger circuit configured to generate a gate-level trigger signal in response to the overvoltage trigger signal received by the overvoltage protection module, and cause the overvoltage protection module to conduct a current corresponding to the transient overvoltage condition.

[0014] Some embodiments provide that: the trigger circuit further includes an optical isolation circuit, which is connected between the comparison circuit and the gate-level trigger circuit and is configured to provide electrical isolation between the comparison circuit and the gate-level trigger circuit.

[0015] Some embodiments include a surge protection device connected between any two phase lines and / or the neutral line.

[0016] In some embodiments, the active energy absorber further comprises a buffer circuit connected in parallel with the overvoltage protection module. The buffer circuit may comprise a resistor and a capacitor connected in series with each other.

[0017] In some embodiments, the active energy absorber includes: a surge protection device connected between any two phase lines and / or the neutral line; an overvoltage protection module including two thyristors connected in anti-parallel to each other; a varistor connected to the overvoltage protection module as a series circuit, the series circuit being connected between the neutral line and / or any two of the phase lines; an inductor connected between the varistor and the surge protection device; and a trigger circuit connected between any two phase lines and / or the neutral line and to the two thyristors, and configured to provide a control signal to the two thyristors in response to detecting an overvoltage condition across the neutral line and any two of the multiple phase lines.

[0018] Some embodiments of the present invention relate to a method of providing power circuit protection. The method may include: using a trigger circuit to sense an overvoltage condition on a power line; and switching an overvoltage protection device into a conduction mode, the conduction mode being configured to clamp the voltage to a voltage limit corresponding to an operating voltage of the power circuit.

[0019] Some embodiments include: after switching the overvoltage protection device to the conducting mode, sensing that the overvoltage condition on the power line is not present; and switching the overvoltage protection device to a non-conducting mode.

[0020] In some embodiments, the power circuit is an alternating current (AC) power circuit, and sensing the overvoltage condition may correspond to a first portion of a voltage waveform. After switching the overvoltage protection to a non-conducting mode, the method may further include: using the trigger circuit to sense another overvoltage condition corresponding to a second portion of the voltage waveform. The overvoltage protection device may be switched to a conducting mode, the conducting mode being configured to clamp the voltage to a second portion of the voltage waveform voltage limit.

[0021] In some embodiments, switching the overvoltage protection device during the first portion of the voltage waveform includes switching a first thyristor, and switching the overvoltage protection device during the second portion of the voltage waveform includes switching a second thyristor connected in anti-parallel with the first thyristor.

[0022] Some embodiments of the present invention relate to a circuit protection device, the circuit protection device comprising a first thyristor, a first varistor, a second thyristor, and a second varistor. The first thyristor comprises a first anode connected to a first power line, a first cathode, and a first gate level. The first varistor is connected to the first anode. The second thyristor comprises: a second anode connected to a second power line, and a second cathode connected to the first cathode, and a second gate level. The second varistor is connected to the second anode and the first varistor.

[0023] In some embodiments, the first varistor is connected to the first cathode and the second varistor is connected to the second cathode.

[0024] Some embodiments may include a trigger circuit connected to the first power line and the second power line and the first gate level and the second gate level, wherein the trigger circuit is configured to provide a control signal to the first thyristor and / or the second thyristor in response to detecting a transient overvoltage condition across the first power line and the second power line.

[0025] In some embodiments, the apparatus further comprises an inductor connected to either the first anode or the second anode.

[0026] In some embodiments, the first varistor includes a plurality of first varistors connected in parallel to one another, and the second varistor includes a plurality of second varistors connected in parallel to one another.

[0027] In some embodiments, the first power line and the second power line include a neutral line and any two of a plurality of phase lines.

[0028] In some embodiments, the apparatus further comprises an inductor connected between a junction of the first varistor and the second varistor and a junction of the first cathode and the second cathode.

[0029] In some embodiments, the device also includes a trigger circuit, which is connected to the first power line and the second power line, to the first gate level and the second gate level, and to the node of the first cathode and the second cathode, wherein the trigger circuit is configured to provide a control signal to the first thyristor and / or the second thyristor in response to detecting a transient overvoltage condition across the first power line and the second power line.

[0030] In some embodiments, the active energy absorber module includes first and second electrical terminals, a module housing, first and second thyristors, and a varistor. The first and second thyristors are enclosed within the module housing and electrically connected between the first and second electrical terminals. The varistor is enclosed within the module housing and electrically connected to at least one of the first and second thyristors between the first and second electrical terminals.

[0031] In some embodiments, the varistor is electrically connected in series with each of the first thyristor and the second thyristor.

[0032] In some embodiments, the first thyristor and the second thyristor are connected in anti-parallel between the first electrical terminal and the second electrical terminal.

[0033] In some embodiments, the active energy absorber module further comprises a second varistor enclosed within the module housing, the first thyristor comprising a first anode and a first cathode, the second thyristor comprising a second anode and a second cathode, the first varistor being electrically connected to the first anode and the first cathode, and the second varistor being electrically connected to the second anode and the second cathode.

[0034] In some embodiments, the active energy absorber module further includes an inductor connected between a junction of the first and second varistors and a junction of the first cathode and the second cathode.

[0035] In some embodiments, the active energy absorber includes a plurality of varistors enclosed within the module housing and electrically connected in parallel with each other between the first and second electrical terminals.

[0036] In some embodiments, the active energy absorber includes a trigger circuit enclosed within the module housing and electrically connected to each of the first and second thyristors.

[0037] In some embodiments, the active energy absorber includes a line port defined in the module housing, and at least one electrical line extending through the line port and electrically connecting the first and second thyristors to a trigger circuit external to the module housing.

[0038] According to some embodiments, the active energy absorber includes an inductor coil enclosed within the module housing and connected in series with the first and second thyristors between the first and second electrical terminals.

[0039] In some embodiments, an inductor coil includes: a helically extending coil strip defining a helical coil channel; and an electrically insulating case including a partition wall portion filling the coil channel.

[0040] In some embodiments, the active energy absorber includes an electrically conductive fusible member enclosed within the module housing. The fusible member melts in response to heat in the active energy absorber and forms an electrical short circuit path across the first electrical terminal and the second electrical terminal.

[0041] According to some embodiments, the module housing includes a first electrode and a second electrode, and the varistor and the first and second thyristors are axially stacked between the first and second electrodes.

[0042] In some embodiments, the first electrode comprises a housing electrode comprising an end wall and an integral side wall, the end wall and the integral side wall together defining a cavity, and the second electrode extends into the cavity.

[0043] In some embodiments, the varistor and the first and second thyristors are disposed in the cavity.

[0044] In some embodiments, the housing electrode is formed of a metal monolith.

[0045] In some embodiments, the active energy absorber includes a biasing device that applies an axial compressive load to the varistor and the first and second thyristors.

[0046] It should be noted that aspects of the present invention described with respect to one embodiment may be incorporated into different embodiments, although not specifically described with respect thereto. That is, all embodiments and / or features of any embodiment may be combined in any manner and / or combination. These and other objects and / or aspects of the present invention are explained in detail in the specification set forth below. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The accompanying drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification. The accompanying drawings illustrate some embodiments of the present invention and together with the description serve to explain the principles of the present invention.

[0048] Figure 1 is a block diagram of a system including conventional surge protection.

[0049] Figure 2 is a block diagram of a system including conventional surge protection.

[0050] Figure 3 is a schematic block diagram illustrating an apparatus for active overvoltage protection according to some embodiments of the present invention.

[0051] Figure 4 is a schematic block diagram illustrating an apparatus for active overvoltage protection according to some embodiments of the present invention.

[0052] Figure 5 is a schematic block diagram illustrating an apparatus for active overvoltage protection according to some embodiments of the present invention.

[0053] Figure 6 is a schematic block diagram illustrating an apparatus for active overvoltage protection according to some embodiments of the present invention.

[0054] Figure 7 is a diagram illustrating some embodiments of the present invention that can be referred to in Figures 3 to 6 Schematic block diagram of a triggering device for use in any of the devices described.

[0055] Figure 8 is a block diagram illustrating operations for providing active overvoltage protection according to some embodiments of the present invention.

[0056] Fig. 9 is a graph of voltage and time under overvoltage conditions for overvoltage protection according to some embodiments of the present invention.

[0057] Fig.10 is a top perspective view of a multi-phase active energy absorber module according to some embodiments of the present invention.

[0058] Fig.11 yes Fig.10 A fragmentary top view perspective view of a multi-phase active energy absorber module.

[0059] Fig.12 yes Fig.10 A fragmentary bottom perspective view of a multi-phase active energy absorber module.

[0060] Fig.13 It is along Fig.11 The line 13-13 is intercepted Fig.10 A fragmentary cross-sectional view of a multi-phase active energy absorber module.

[0061] Fig.14 is a top perspective view of an active energy absorber system according to some embodiments of the present invention.

[0062] Fig.15 According to some embodiments of the present invention and formed Fig.14 An exploded top perspective view of an active energy absorber module that is part of an active energy absorber system.

[0063] Fig.16 It is along Fig.14 The line 16-16 is intercepted Fig.15 Cross-section of the active energy absorber module.

[0064] Fig.17 is a cross-sectional view of an active energy absorber module according to another embodiment of the present invention.

[0065] Fig.18 is formed Fig.17 A top perspective view of a triggering module of a portion of an active energy absorber module.

[0066] Fig.19 is a cross-sectional view of an active energy absorber module according to another embodiment of the present invention.

[0067] Fig. 20 is a top perspective view of an active energy absorber module according to another embodiment of the present invention.

[0068] Fig.21 It is along Fig. 20 The line 21-21 is intercepted Fig. 20 Cross-section of the active energy absorber module.

[0069] Fig. 22 is formed Fig. 20 An exploded top perspective view of a coil assembly of a portion of an active energy absorber module.

[0070] Fig.23 is formed Fig. 22A bottom perspective view of a box body of a portion of a coil assembly.

[0071] Fig.24 is a cross-sectional view of an active energy absorber module according to another embodiment of the present invention.

[0072] Fig.25 is formed Fig.24 An exploded top perspective view of an active component subassembly of a portion of an active energy absorber module.

[0073] Fig.26 is a schematic block diagram illustrating an apparatus for active overvoltage protection according to some embodiments of the present invention.

[0074] Fig. 27 is a cross-sectional view of an active energy absorber according to another embodiment of the present invention.

[0075] Fig.28 yes Fig. 27 An exploded perspective view of the active energy absorber.

[0076] Fig.29 is a cross-sectional view of an active energy absorber according to another embodiment of the present invention.

[0077] Fig.30 is a cross-sectional view of an active energy absorber according to some embodiments of the present invention.

[0078] Fig.31 is a schematic block diagram illustrating an apparatus for active overvoltage protection according to some embodiments of the present invention.

[0079] Fig.32 is a cross-sectional view of an active energy absorber according to some embodiments of the present invention. DETAILED DESCRIPTION

[0080] Hereinafter, the present invention will now be more fully described with reference to the accompanying drawings showing illustrative embodiments of the present invention. In the accompanying drawings, the relative sizes of some areas or features may be exaggerated for clarity. However, the present invention may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that the disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art.

[0081] It will be understood that when an element is referred to as being "coupled" or "connected" to another element, it may be directly coupled or connected to the other element, or there may be intervening elements. Conversely, when an element is referred to as being "directly coupled" or "directly connected" to another element, there are no intervening elements. Like reference numerals refer to like elements throughout.

[0082] In addition, in order to simplify the description of the relationship between one element or feature illustrated in the drawings and another (or more) element or feature, spatially relative terms such as "under", "below", "lower", "on", "upper", etc. may be used herein. It will be understood that in addition to the orientation depicted in the drawings, the spatially relative terms are intended to include different orientations of the device in use or operation. For example, if the device in the drawings is flipped, then the elements described as "under other elements or features" or "under other elements or feature structures" are oriented as "on other elements or feature structures". Thus, the example term "under" can include the orientations of "on" and "under". The device can be oriented otherwise (rotated 90 degrees or in other orientations) and the spatially relative descriptive terms used herein can be interpreted accordingly.

[0083] Well-known functions or constructions may not be described in detail for brevity and / or clarity.

[0084] As used herein, the expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0085] The terminology used herein is intended only to describe specific embodiments and is not intended to limit the present invention. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the terms "comprises" and / or "comprising" when used in this specification specify the presence of stated features, integers, steps, operations, elements, and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts, and combinations thereof.

[0086] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. It will also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and these terms should not be interpreted as idealized or overly formal meanings, unless explicitly defined herein.

[0087] To date, the type of circuit used to provide protection against transient overvoltages, transient overvoltages and surge / lightning currents may include a varistor that can be connected directly between power lines. The difference between a standard varistor used to provide protection against transient overvoltages and surge currents and a varistor used to provide protection against transient overvoltages may be that the second type may be in conduction mode for a long period of time (in the range of 100ms to 300ms or even more) for currents that may range between a few amperes and several thousand amperes, while the first type may be in conduction mode for a very limited period of time (in the range of a few μs to 5ms) for currents that may range between a few hundred amperes and more than 100 kA.

[0088] Therefore, when a varistor is used to provide protection against transient overvoltages, the varistor will conduct a significant amount of current from the power source in order to clamp the overvoltage generated by the power source. This will require the varistor to absorb a significant amount of energy over a long period of time. In addition, when such a varistor fails, at the end of the useful life of the device, the failure mode will be a low impedance (i.e., short circuit) failure mode.

[0089] Now refer to Figure 3 , Figure 3 is a schematic block diagram illustrating an apparatus for active overvoltage protection according to some embodiments of the present invention. An active energy absorber 100 may be connected between power lines 70, 72 in a power distribution system and / or component. The power lines 70, 72 may include a power line and / or a neutral line in a single-phase power system or a phase line and / or a neutral line in a multi-phase system (e.g., a three-phase power system). Thus, the active energy absorber 100 may be connected between two phase lines or power lines and / or between a phase line or power line and a neutral line. The active energy absorber 100 may provide high energy absorption capability and safe end-of-life operation for protection against transient overvoltages.

[0090] Some embodiments provide that the active energy absorber 100 can selectively conduct fault current in response to an overvoltage condition. For example, some embodiments provide that when the active energy absorber 100 is in a conduction mode, the overvoltage condition can be clamped to a specific voltage by absorbing energy corresponding to an overvoltage fault condition that exceeds a clamping voltage. Some embodiments are directed to providing protection for transient overvoltage conditions originating from an electric power system that can persist for a longer period of time than transient and / or surge voltages. In use and operation, some embodiments provide that the transient overvoltage can be clamped to a voltage that is approximately 2 times and / or less than approximately 2 times the system operating voltage. For example, in a 220 volt system, an embodiment may set the threshold voltage to approximately 450 volts.

[0091] In some embodiments, the active energy absorber 100 includes an overvoltage protection module 101, which includes two thyristors 102 and 104 connected in anti-parallel to each other. The thyristors 102 and 104 of the overvoltage protection module 101 can be connected in series with a varistor 106. The series circuit including the varistor 106 and the overvoltage protection module 101 can be connected between any two power lines and the neutral line 70, 72.

[0092] Some embodiments provide that the active energy absorber 100 includes a trigger circuit 110 connected to the power line / neutral line 70, 72 and the overvoltage protection module 101. The trigger circuit 110 can be configured to provide a control signal to the overvoltage protection module 101 in response to detecting a transient overvoltage condition across the power line / neutral line 70, 72. For example, in response to detecting a voltage across the power lines 70 and 72 exceeding a threshold voltage, the trigger circuit 110 can generate a signal to turn on one or both of the thyristors 102, 104 (i.e., form a low resistance current conduction path). Once the thyristors 102, 104 are turned on, the varistor 106 can absorb electrical energy to clamp the voltage between the power lines 70, 72 to a clamping voltage that can correspond to the threshold voltage.

[0093] As an example, for a 240V system, the peak voltage may be 336V. A varistor 106 having a maximum continuous operating voltage (MCOV) of 250V AC as close to the nominal voltage as possible may be used so that during normal conditions the MOV 106 will not conduct any current. Typically, such a MOV may have a voltage protection level of about 1000V. During a TOV event, when the voltage rises above a predetermined threshold (e.g., 600V), then the trigger circuit will trigger one of the thyristors 102, 104 depending on the AC voltage polarity. Once each of the thyristors 102, 104 is turned on, the MOV 106 may begin to conduct heavily in order to clamp the voltage. During a TOV event, when the voltage begins to drop close to the voltage corresponding to normal operation, the MOV 106 may begin to become increasingly resistive and may begin to reduce current. The MOV 106 may conduct very little leakage current (e.g., about 1 mA) at 336V. Therefore, when the voltage decreases to a value close to the operating system voltage, the current through the thyristors 102, 104 may be reduced to a very low value and thus the thyristors 102, 104 may block, for example, typically the thyristors will be in conduction mode only when the current through the thyristors exceeds a certain level (e.g., about 200mA).

[0094] However, there are power systems that may require protection at lower voltage levels, for example, 700 V instead of 1000 V. In this case, to reduce the level of protection, a varistor 106 with a lower MCOV, i.e., a thinner varistor disk, may be used. For example, the varistor may have an MCOV of 150 V AC instead of 250 V AC.

[0095] In some embodiments, the fault current corresponding to the overvoltage condition may exceed the energy absorption capacity of a single varistor 106. In such a case, the capacity of the varistor 106 may be increased by using multiple varistors 106 arranged in parallel with each other. Some embodiments provide that multiple parallel varistors 106 may be configured in a single device.

[0096] In addition, an inductor 120 may be provided in one of the lines 70, 72 to protect the thyristors 102, 104 from significant instantaneous current changes (di / dt) in the event of a surge event due to the dV / dt to which the thyristors 102, 104 will be exposed when the thyristors 102, 104 self-trigger during a transient overvoltage event or surge current. In some embodiments, the inductor 120 may also be considered part of the power system (cable length, transformer, etc.). Some embodiments provide that the inductor 120 may be added to the lines 70, 72.

[0097] Some embodiments provide that the power distribution system / device is an alternating current (AC) system / device. In such embodiments, the anti-parallel thyristors 102, 104 may be activated alternately to correspond to different portions of the voltage waveform. For example, if an overvoltage condition occurs during the positive half of the voltage waveform, the second thyristor 104 may be turned on to become conductive as long as the voltage remains above the voltage threshold in that half of the waveform. Once the voltage in that portion of the cycle drops below the threshold voltage, the varistor 106 may stop conducting because the voltage is sufficiently low and the thyristor 104 may be blocked. If the fault condition persists into the next portion of the voltage waveform, when the negative voltage exceeds the voltage threshold in the negative direction, the thyristor 102 may be turned on to become conductive as long as the voltage is greater than the voltage threshold in the negative direction in that half of the waveform.

[0098] Some embodiments provide that the active energy absorber 100 described above can protect against transient overvoltages having a slow rise time of voltage. However, the active energy absorber 100 may not provide adequate protection during surge events and transient overvoltages. In this regard, the apparatus for active overvoltage protection may further include a surge protection device (SPD) 130, which may be connected to the power lines 70, 72 in parallel with the active energy absorber 100. The SPD 130 may be configured to protect devices connected to the SPD 130 during overvoltage conditions by conducting a limited amount of current corresponding to a surge or transient overvoltage condition. Some embodiments provide that the SPD 130 may be used in circuits that are threatened by transient overvoltages and surge currents because during these events, overvoltages and high voltage rise rates will be applied to the thyristors 102, 104 for a period of at least several μs. This may be because the response time of the trigger circuit 110 that will trigger the thyristors 102, 104 and connect the varistor 106 to the power lines 70, 72 to clamp the overvoltage may be longer than the few μs. Thus, if such an overvoltage exceeds the maximum operating voltage of the thyristors 102, 104, the overvoltage that may be applied for several μs may damage the thyristors 102, 104.

[0099] In some embodiments, the device for active overvoltage protection including the active energy absorber 100 described herein may be implemented as a device that uses discrete components (i.e., a coil, a thyristor, and one or more varistors in parallel) that make up the various parts of the circuit. Some embodiments provide that the device for active overvoltage protection including the active energy absorber described herein may be implemented as the energy absorber described above.

[0100] Now refer to Figure 4 , Figure 4 2 is a schematic block diagram of an apparatus for active overvoltage protection according to some embodiments of the present invention. The apparatus for active overvoltage protection includes an SPD 230 and an active energy absorber 200, the active energy absorber 200 includes a varistor 206, a trigger circuit 210, and an overvoltage protection module 201 including thyristors 202 and 204. The SPD 230 and the active energy absorber 200 are similar to the above-mentioned Figure 3 The SPD 130 discussed is similar to the active energy absorber 100, which includes a varistor 106, a trigger circuit 110, and an overvoltage protection module 101 including thyristors 102, 104. As such, for the sake of brevity, the discussion of these components will be omitted.

[0101] and Figure 3 compared to, Figure 4The device provides that the inductor 208 is a component of the active energy absorber 200. For example, the inductor 208 may be connected in series with a series circuit including a varistor 206 and anti-parallel thyristors 202, 204 of the overvoltage protection module 201.

[0102] Now refer to Figure 5 , Figure 5 3 is a schematic block diagram illustrating an apparatus for active overvoltage protection according to some embodiments of the present invention. The apparatus for active overvoltage protection includes an SPD 330, an inductor 320, and an active energy absorber 300, wherein the active energy absorber 300 includes a varistor 306, a trigger circuit 310, and an overvoltage protection module 301 including thyristors 302 and 304. The SPD 330, the inductor 320, and the active energy absorber 300 are similar to the above-mentioned Figure 3 The discussed SPD 130, inductor 120, and active energy absorber 100 are similar, and active energy absorber 100 includes a varistor 106, a trigger circuit 110, and an overvoltage protection module 101 including thyristors 102, 104. As such, for the sake of brevity, the discussion of these components will be omitted.

[0103] In some embodiments, active energy absorber 300 may include a snubber circuit 312 connected in parallel with overvoltage protection module 301. Some embodiments provide that snubber circuit 312 includes a resistor 316 and a capacitor 314 connected in series with each other.

[0104] In some embodiments, snubber circuits 312 used in parallel with thyristors 302, 304 can reduce and / or eliminate self-triggering of thyristors 302, 304 during surge events and / or transient overvoltage events. In this case, thyristors 302, 304 can be triggered only by trigger circuit 310, which is only reacting to transient overvoltage events. In some embodiments, inductor 320 can be omitted because it may not be desirable for thyristors 302, 304 to conduct surge currents.

[0105] Now refer to Figure 6 , Figure 6 is a schematic block diagram illustrating an apparatus for active overvoltage protection according to some embodiments of the present invention. An active energy absorber 400 may be connected between power lines 70, 72 in a power distribution system and / or component. The power lines 70, 72 may include power lines and / or neutral lines in a single-phase power system or phase lines and / or neutral lines in a multi-phase system (e.g., a three-phase power system). Thus, the active energy absorber 400 may be connected between two phase lines or power lines and / or between a phase line or power line and a neutral line.

[0106] Some embodiments provide that the active energy absorber 400 can selectively conduct fault current in response to an overvoltage condition. For example, some embodiments provide that when the active energy absorber 400 is in a conduction mode, the overvoltage condition can be clamped to a specific voltage by absorbing energy corresponding to an overvoltage fault condition that exceeds a clamping voltage. Some embodiments are directed to providing protection for transient overvoltage conditions originating from a power system that can persist for a longer period of time than transient and / or surge voltages.

[0107] In some embodiments, the active energy absorber 400 includes the Figure 3 The trigger circuit 410 discussed above is similar to the trigger circuit 110. As such, additional description of the trigger circuit 410 will be omitted.

[0108] The active energy absorber 400 may include a first thyristor 404 including a first anode, a first cathode, and a first gate connected to the first power line 70, and a first varistor 406 connected to the anode and cathode of the first thyristor 404. In this regard, the first thyristor 404 and the first varistor 406 may be connected in parallel to each other and each connected to the first power line 70. The active energy absorber 400 may include a second thyristor 402 including a second anode connected to the second power line 72, a second cathode connected to the cathode of the first thyristor 404, and a second gate. The second varistor 408 is connected to the anode and cathode of the second thyristor 402. In this regard, the second thyristor 402 and the second varistor 408 may be connected in parallel to each other and each connected to the second power line 72.

[0109] In some embodiments, the circuitry of active energy absorber 400 may include SPD functionality. As such, some embodiments provide that active energy absorber 400 may be used without an additional and / or external SPD.

[0110] In addition, during surge events and transient overvoltages, due to the internal parasitic capacitance of the thyristors 402, 404 between the gate level and the anode and between the gate level and the cathode, the thyristors 402, 404 can be self-triggered. Conventionally, in order to avoid the thyristors 402, 404 from self-triggering in surge events and transient overvoltage events, manufacturers can make the parasitic capacitance as low as possible. However, when current is applied, the parasitic capacitance will be higher, which can improve the convenience of manufacturing. In this regard, the device can show improved trigger sensitivity during surge events and transient overvoltage events. In this way, before the trigger thyristors 402, 404 are triggered and the voltage is clamped at the protection level of the varistors 406, 408, the voltage may not reach a very high value. In this regard, whether the event is a transient overvoltage, a surge current or a transient overvoltage, the device can be uniformly clamped at the voltage level of a single varistor 406, 408.

[0111] The active energy absorber 400 may not use a snubber circuit while the snubber circuit may prevent false triggering of the thyristors due to high dV / dt during surge events or transient overvoltages. Alternatively, the self-triggering capability of the thyristors 402, 404 may clamp the voltage across a single varistor.

[0112] Some embodiments provide that an inductor 420 may optionally be used to reduce the di / dt through the thyristors 402, 404 when the thyristors 402, 404 are conducting surge currents. Some embodiments provide that the power lines 70, 72 themselves have sufficient inductance due to the length of the power lines 70, 72, the size of the cables, and any transformers installed upstream of the device. However, adding an inductor 420 between the power line 70 and the device may result in an increase in the level of protection (clamping voltage) that the device will experience during surge events and transient overvoltages. In this regard, if the inductance of the power system is insufficient, additional in-line modules may be added to increase the total inductance of the power line. Some embodiments provide that since two varistors are used in the same device, energy absorption may be shared between the two varistors during conduction.

[0113] Additionally, the device may provide an independent self-triggering operation that may be connected between two lines in a power system and provide protection against transient overvoltages, instantaneous overvoltages, and / or surge / lightning currents.

[0114] Now refer to Figure 7 , Figure 7 is a diagram illustrating some embodiments of the present invention that can be referred to in Figures 3 to 6Schematic block diagram of a trigger device used in any of the devices described. The trigger device 510 may include a rectifier 512, which is configured to receive an AC line voltage from the power lines 70, 72 and convert the AC line voltage into a DC output voltage, which is a voltage level corresponding to the AC line voltage. The comparison circuit 514 may receive a voltage level signal and a voltage reference signal Vref. The output of the comparison circuit 514 may be based on a comparison between the voltage level signal and the voltage reference signal Vref. For example, if the voltage level signal is less than Vref, the output of the comparison circuit 514 may correspond to a normal operating voltage level on the power lines 70, 72. Conversely, if the voltage level signal is greater than Vref, the output of the comparison circuit may change the state to indicate that an overvoltage condition exists.

[0115] The output of the comparison circuit 514 may be received by one or more signal driver circuits 516, which may amplify, invert, and / or stabilize the output state of the comparison circuit 514. In some embodiments, an optical isolation circuit 518 that receives an input corresponding to the output of the comparison circuit 514 may provide electrical isolation between the comparison circuit 514 and a gate level trigger circuit 520, which is configured to generate one or more gate level trigger signals if the output corresponding to the comparison circuit indicates an overvoltage condition on the power lines 70, 72. The gate level trigger signal(s) may be received by the overvoltage protection module and may cause the overvoltage protection module to conduct a current corresponding to the transient overvoltage condition. For example, the gate level trigger signal may be received at each of the two thyristors in the active energy absorber disclosed herein.

[0116] Now refer to Figure 8 , Figure 8 8 is a block diagram illustrating operations for providing active overvoltage protection according to some embodiments of the present invention. According to some methods, operations may include: using a trigger circuit to sense an overvoltage condition on a power line (block 810). The power line may be a phase power line and / or a single-phase power line in a multi-phase power system. The overvoltage condition may be associated with another power line and / or a neutral line. Some embodiments provide that the overvoltage condition may be a transient overvoltage system that may last for a considerable period of time, for example, 10 ms to 300 ms or more, compared to a surge or transient overvoltage event that may have a much shorter duration.

[0117] In response to detecting an overvoltage condition, the operation may include switching the overvoltage protection device to a conduction mode (block 820). When the overvoltage protection device is switched to the conduction mode, the voltage on the power line is clamped to a voltage limit corresponding to the operating voltage of the power circuit. For example, the voltage limit may be clamped to some multiple of the operating voltage of the power circuit. In some embodiments, the multiple may be in the range of 1.4 to 3.0, whereby the voltage is clamped to a voltage of 1.4 to 3.9 times the system operating voltage. In some embodiments, the multiple may be approximately 2, whereby the voltage is clamped to a voltage of approximately 2 times the system operating voltage. Some embodiments provide that the overvoltage protection device includes one or more thyristors connected in series with the SPD and switched to a conduction mode. In such embodiments, the SPD may be used to clamp the voltage by absorbing energy corresponding to the fault current.

[0118] Once the overvoltage condition has passed, operations may include sensing that the overvoltage condition on the power line is not present (block 830). This may be done after the thyristor exhibits the following characteristics: the thyristor disconnects from the power line when the current conducted drops below a certain threshold (e.g., about 200 mA). As the voltage drops, at some point the voltage will reach a level below which the MOV connected in series to the thyristor will only allow less than about 200 mA of current to be conducted therefrom. This may also mean that the TOV condition has passed. In response to detecting that the overvoltage condition is not present, the overvoltage protection device may be switched to a non-conducting mode (block 840).

[0119] In some embodiments, the power circuit is an alternating current (AC) power circuit, and the sensed overvoltage condition may correspond to a first portion of the voltage waveform, and after switching the overvoltage protection to a non-conducting mode, the trigger circuit may sense another overvoltage condition corresponding to a second portion of the voltage waveform. In such embodiments, the overvoltage protection device may be switched to a conducting mode configured to clamp the voltage to a second portion of the voltage waveform voltage limit. For example, some embodiments provide that the overvoltage protection device is switched using a first thyristor during execution of the first portion of the voltage waveform, and the overvoltage protection device is switched using a second thyristor connected in anti-parallel with the first thyristor during execution of the second portion of the voltage waveform.

[0120] Fig. 9is a graph of voltage and time under an overvoltage condition based on overvoltage protection of some embodiments of the present invention. As shown, the overvoltage condition begins at time T1. Once the voltage level reaches a voltage threshold (V-threshold) at time T2, the overvoltage protection turns on to become conductive and clamps the voltage to a clamping voltage (V-clamp). As the overvoltage condition weakens, the voltage level decreases from the clamping voltage V-clamp to the operating voltage V-operating until the voltage decreases to a level below the clamping voltage. During the voltage reduction, once the fault current reaches a given trigger fault current level, the overvoltage protection turns off and thus stops conducting current at time T3. For example, some embodiments provide that when a given trigger fault current reaches approximately 220mA, the overvoltage protection turns off, however, the given trigger fault current may be greater than or less than 220mA.

[0121] Reference Figures 10 to 13 , which shows Figure 3 The illustrated embodiment is a multi-phase active energy absorber module 901, which is a three-phase implementation and thus includes two phases, respectively. Figure 3 The active energy absorber subassemblies 900 correspond to one of the active energy absorbers 100 of each phase. That is, the active energy absorber 100 of each phase is embodied in a corresponding subassembly 900. Each subassembly 900 includes an MOV module 920 (corresponding to MOV 106), two thyristors 910, 912 (corresponding to thyristors 102, 104), a trigger circuit 930 (corresponding to the trigger circuit 110), and a fuse 934 as a discrete component. Each subassembly 900 is electrically connected to and mechanically mounted on an electrically conductive neutral plate 903 and includes a corresponding line terminal 902. The neutral terminal 904 is also connected to the neutral plate 903. The trigger circuit 930 is provided on a PCB 932. The subassembly 900 and the neutral plate 903 are accommodated in a module housing 906.

[0122] In some embodiments, each MOV module 920 may be constructed as disclosed in one or more of U.S. Pat. Nos. 6,038,119 to Atkins et al. and 6,430,020 to Atkins et al., the disclosures of which are incorporated herein by reference. Fig.13As shown, each MOV module 920 includes a metal shell electrode 922, a metal piston electrode 924, and a plurality of varistor wafers 926 stacked between a head 924A of the electrode 924 and an electrode end wall 922A of the shell 922. The varistor wafers 926 are electrically connected in parallel between the head 924A and the inner surface of the end wall 922A by an electrically conductive interconnection member 928. The electrodes 922 and 924 together form a chamber 921A, in which the varistor 926 is accommodated and encapsulated.

[0123] Figure 4 The circuit may be implemented using discrete components for each of the circuit components, with reference to Figures 10 to 13 The described embodiment is similar. In this case, each subassembly 900 is also provided with an inductor corresponding to the inductor 208 .

[0124] In other embodiments, Figure 6 The circuit is implemented or packaged as an active energy absorber module comprising a single integrated device, wherein the varistor 106 and the thyristors 102, 104 are encapsulated in a rugged housing assembly. Figures 14 to 16 , in which an active energy absorber system 1001 according to an embodiment of the present invention is shown. The system 1001 includes a modular active energy absorber unit or module 1000 according to an embodiment of the present invention and an external trigger circuit 1002. For each Figure 6 The active energy absorber 400 in the embodiment of the present invention may use a system 1001. The trigger circuit 1002 may include Figure 6 The trigger circuit 410 may be any suitable device. The trigger circuit 1002 may be packaged in a protective housing.

[0125] The active energy absorber module unit 1000 has a longitudinal axis AA ( Fig.16 ). The active energy absorber module 1000 includes a first electrode or housing 1022, a piston-shaped second electrode 1024, four spring washers 1028E, a flat washer 1028D, an insulating ring member 1028C, three O-rings 1030A-1030C, an end cap 1028A, a retaining clip 1028B, a fusible member 1032, an insulating sleeve 1034, and a cable gland 1036. The active energy absorber module unit also includes an active component subassembly 1040, which includes three internal interconnect components 1054, 1056, 1058, two varistor components 1042, 1044, two thyristors 1046, 1048, two contact plates 1050, 1052, two gate level connectors 1062D, and two signal cables 1062A-1062B.

[0126] Components 1022, 1024, 1028A-C collectively form a housing assembly that defines a sealed, enclosed chamber 1026. Components 1022, 1024, 1028A-E, 1032, and 1040 are axially disposed in the enclosed chamber 1026 along the longitudinal axis AA between the housing and the electrode.

[0127] The housing 1022 has an end electrode wall 1022A and an integral cylindrical side wall 1022B extending from the electrode wall 1022A. The side wall 1022B and the electrode wall 1022A form a chamber or cavity 1022C that communicates with the opening 1022D. A threaded post 1022E protrudes axially outward from the electrode wall 1022A. A wiring hole or port 1022F extends through the side wall 1022B.

[0128] The electrode wall 1022A has an inwardly facing, generally planar contact surface 1022G. An annular clamp groove 1022H is formed in the inner surface of the side wall 1022B. According to some embodiments, the housing 1022 is formed of aluminum. However, any suitable electrically conductive metal may be used. According to some embodiments, the housing 1022 is unitary, and in some embodiments is monolithic. The housing 1022 as shown is cylindrical, but may be formed into different shapes.

[0129] The inner electrode 1024 has a head 1024A disposed in the cavity 1022C and an integral shaft 1022B protruding outwardly through the opening 1022D.

[0130] The head 1024A has a generally planar contact surface 1024C facing the contact surface 1022G of the electrode wall 1022A. A pair of integral, annular, axially spaced flanges 1024D extend radially outward from the shaft 1024B and define an annular, laterally open groove 1024E therebetween. For example, a threaded opening 1024F is formed in the end of the shaft 1024B to receive a bolt for securing the electrode 1024 to a busbar. An annular, laterally open groove 1024G is defined in the shaft 1024B.

[0131] According to some embodiments, electrode 1024 is formed of aluminum. However, any suitable electrically conductive metal may be used. According to some embodiments, electrode 1024 is monolithic, and in some embodiments is unitary.

[0132] The electrodes 1022 , 1024 , the insulating ring 1028C, and the end cap 1028A collectively define an enclosed chamber 1026 , which houses the fusible member 1032 and the active component subassembly 1040 .

[0133] An annular gap is defined radially between the head 1024A and the nearest adjacent surface of the sidewall 1022B. According to some embodiments, the gap has a radial width ranging from about 3 mm to about 10 mm.

[0134] Fusible member 1032 is annular and mounted on electrode 1024 in recess 1024E. Fusible member 1032 is spaced apart from sidewall 1022B by a distance sufficient to electrically isolate fusible member 1032 from sidewall 1022B.

[0135] Fusible member 1032 is formed of a heat-fusible electrically conductive material. According to some embodiments, fusible member 1032 is formed of a metal. According to some embodiments, fusible member 1032 is formed of an electrically conductive metal alloy. According to some embodiments, fusible member 1032 is formed of a metal alloy selected from the group consisting of an aluminum alloy, a zinc alloy, and / or a tin alloy. However, any suitable electrically conductive metal may be used.

[0136] According to some embodiments, the fusible member 1032 is selected such that its melting point is greater than a specified maximum standard operating temperature. The maximum standard operating temperature may be the expected maximum temperature in the fusible member 1032 during normal operation (including handling overvoltage surges within the range designed for the system 1001) rather than during operation that would result in thermal runaway if not controlled. According to some embodiments, the fusible member 1032 is formed of a material having a melting point ranging from about 80°C to about 160°C and, according to some embodiments, ranging from about 130°C to about 150°C. According to some embodiments, the melting point of the fusible member 1032 is at least 20°C less than the melting points of the housing 1022 and the electrode 1024, and, according to some embodiments, at least 40°C less than the melting points of these components.

[0137] According to some embodiments, the fusible member 1032 has a range of about 0.5×10 6 Siemens / meter (S / m) to about 4×10 7 S / m and according to some embodiments ranges from about 1×10 6 S / m to about 3×10 6 Conductivity in S / m.

[0138] Two varistors 1042, 1044, two thyristors 1046, 1048, two contact plates 1050, 1052, an insulating member 1060, and three interconnecting members 1054, 1056, 1058 are stacked axially in the chamber 1026 between the electrode head 1024 and the electrode wall 1022 and form an active component subassembly 1040. The subassembly 1040 is connected to the electrode head 1024 in the following manner. Figure 6 The portion of the circuit shown corresponds to or forms Figure 6Portions of the circuit shown: varistor 1042 corresponds to varistor 406, varistor 1044 corresponds to varistor 408, thyristor 1046 corresponds to thyristor 402, thyristor 1048 corresponds to thyristor 404, and trigger circuit 1002 corresponds to trigger circuit 410. Interconnect members 1054, 1056 and contact plates 1050, 1052 are shown in FIG. Figure 6 The varistors 1042 , 1044 , thyristors 1046 , 1048 , and trigger circuit 1002 are electrically interconnected in the manner shown in .

[0139] Each varistor member 1042,1044 has a first and second contact surface 1043 that is opposite and substantially planar. According to some embodiments, each varistor member 1042,1044 is a varistor sheet (i.e., sheet-shaped or disc-shaped). However, the varistor members 1042,1044 can be formed into other shapes. The thickness and diameter of the varistor sheets 1042,1044 will depend on the varistor characteristics required for the specific application. In some embodiments, each varistor sheet 1042,1044 has a diameter-to-thickness ratio of at least 3. In some embodiments, the thickness of each varistor sheet 1042,1044 is in the range of about 1.5mm to about 15mm.

[0140] The varistor sheets 1042, 1044 may comprise sheets of varistor material coated with a conductive coating on either side so that the exposed surface of the coating acts as a contact surface. For example, the coating may be formed of aluminum, copper or silver.

[0141] The varistor material may be any suitable material commonly used for varistors, i.e. a material that exhibits non-linear resistance characteristics with applied voltage. Preferably, the resistance becomes very low when a specified voltage is exceeded. For example, the varistor material may be a doped metal oxide or silicon carbide. Suitable metal oxides include zinc oxide compounds.

[0142] The two thyristors 1046, 1048 can be constructed in the same or similar manner. In some embodiments and as shown, the thyristors 1046, 1048 are sheet-shaped or disc-shaped. In some embodiments, each thyristor 1046, 1048 has a diameter-to-thickness ratio of at least 15. In some embodiments, the thickness of each thyristor 1046, 1048 is in the range of about 1.5 mm to about 10 mm.

[0143] It will be appreciated that in Fig.16, the internal structure and components of the thyristors 1046, 1048 are not shown in detail. Each thyristor 1046, 1048 includes a body 1045A and an anode 1045C and a cathode 1045B on axially opposite sides of the body 1045A. The anode 1045C and the cathode 1045B have substantially planar contact surfaces. Each thyristor 1046, 1048 also includes a gate or control terminal 1045F ( Fig.15 ). Gate terminal 1045F is located at the center of the same plate as anode 1045B and is surrounded by (but electrically isolated from) cathode 1045B. Ring insulator 1045G is axially inserted between anode 1045C and cathode 1045B and electrically isolates anode 1045C from cathode 1045B.

[0144] Suitable thyristors for thyristors 1046, 1048 may be constructed as disclosed, for example, in US Pat. No. 4,956,696 to Hoppe et al., the disclosure of which is incorporated herein by reference.

[0145] Reference Fig.16 , the cable gland 1036 is attached in the line port 1022F. The signal cables 1062A, 1062B extend through the line port 1022F and the cable gland 1036 and enter the chamber 1026. The cable gland 1036 is fixed in the line port 1022F. The cable gland 1036 is used to mechanically hold or fix the line in the port 1022F (providing strain relief) and completely seal, plug or close the opening in the side wall 1022B (e.g., in an airtight manner).

[0146] The signal cable 1062A includes a gate line 1762GA electrically terminated at the control terminal 1045F of the thyristor 1046. The signal cable 1062A also includes a reference line electrically terminated at the cathode 1045B of the thyristor 1046. The signal cable 1062B includes a gate line 1762GB electrically terminated at the control terminal 1045F of the thyristor 1048. The signal cable 1062B also includes a reference line electrically terminated at the cathode 1045B of the thyristor 1048.

[0147] Gate level lines 1062GA, 1062GB of cables 1062A, 1062B terminate to and are electrically and mechanically connected by gate level connectors 1062D to control terminals 1045F of thyristors 1046, 1048. Each gate level connector 1062D may include a spring 1062E that loads or biases the gate level connector 1062D against the associated control terminal 1045F.

[0148] The reference line of the cables 1062A, 1062B can be a thin wire or foil, for example, inserted between each cathode 1045B and the opposite side of the adjacent contact plate 1050, 1052. In some embodiments, the reference line is connected (e.g., by welding) to a thin metal plate (e.g., having a thickness ranging from about 0.1 mm to 1 mm; for simplicity, not shown). The triggering of each thyristor 1046, 1048 is accomplished by two lines (i.e., a gate level line and a reference line) of the corresponding signal cables 1062A, 1062B.

[0149] In other embodiments, for example, the reference lines of cables 1062A and 1062B may be mechanically terminated and electrically connected (e.g., by welding) to bridge portions 1057B of interconnect members 1054 and 1056, respectively, as described below with reference to Fig. 27 In this case, the reference line of cable 1062A will be electrically connected to its cathode 1045B through interconnect member 1054 and contact plate 1050, and the reference line of cable 1062B will be connected to its cathode 1045B through interconnect member 1056 and contact plate 1052.

[0150] The contact plates 1050, 1052 are electrically conductive. Each contact plate 1050, 1052 is disc-shaped and has opposing contact surfaces 1051A. Each contact plate 1050, 1052 also has formed therein a central through hole 1051B and a slot 1051C extending radially from the through hole 1051B to the outer periphery of the contact plate 1050, 1052. Each control line or gate-level line of the signal cable 1062A, 1062B is routed through the slot 1051C of the corresponding contact plate 1050, 1052, and each associated gate-level connector 1062D is placed in the through hole 1051B of the corresponding contact plate 1050, 1052.

[0151] According to some embodiments, the contact plates 1050, 1052 are formed of a copper alloy. However, any suitable electrically conductive metal may be used. According to some embodiments, the contact plates 1050, 1052 are monolithic, and in some embodiments are unitary.

[0152] The interconnect members 1054, 1056, 1058 are electrically conductive. Each interconnect member 1054, 1056, 1058 includes a pair of axially spaced, disc-shaped contact portions 1057A joined by a bridge portion 1057B.

[0153] According to some embodiments, the interconnect members 1054, 1056, 1058 are formed of copper. However, any suitable electrically conductive metal may be used. According to some embodiments, the interconnect members 1054, 1056, 1058 are monolithic, and in some embodiments are unitary.

[0154] Insulating member 1060 can be a relatively thin layer or disk of electrically insulating material. In some embodiments, insulating member 1060 has a thickness ranging from about 1 mm to about 10 mm.

[0155] According to some embodiments, insulating member 1060 is formed of a hard, high temperature polymer, and in some embodiments, a hard, high temperature thermoplastic. In some embodiments, insulating member 1060 is formed of mica.

[0156] According to some embodiments, the insulating member 1060 is formed of a material having a melting point greater than that of the fusible member 1032. According to some embodiments, the insulating member 1060 is formed of a material having a melting point ranging from about 120°C to 200°C.

[0157] According to some embodiments, the insulating member 1060 material can withstand a voltage of 25 kV per mm thickness.

[0158] According to some embodiments, insulating member 1060 has a thickness ranging from about 0.1 mm to 10 mm.

[0159] The insulating sleeve 1034 is tubular and generally cylindrical. According to some embodiments, the insulating sleeve 1034 is formed of a high temperature polymer, and, in some embodiments, a high temperature thermoplastic. In some embodiments, the insulating sleeve 1034 is formed of polyetherimide (PEI), such as ULTEM available from SABIC of Saudi Arabia. TM Thermoplastics. In some embodiments, membrane 1060 is formed from unreinforced polyetherimide.

[0160] According to some embodiments, the insulating sleeve 1034 is formed of a material having a melting point greater than a melting point of the fusible member 1032. According to some embodiments, the insulating sleeve 1034 is formed of a material having a melting point ranging from about 120°C to 200°C.

[0161] According to some embodiments, the insulating sleeve 1034 material can withstand a voltage of 25 kV per mm thickness.

[0162] According to some embodiments, the insulating sleeve 1034 has a thickness ranging from about 0.1 mm to 2 mm.

[0163] Spring washers 1028E surround shaft 1024B. Each spring washer 1028E includes a hole for receiving shaft 1024B. The lowest spring washer 1028E abuts against the top surface of head 1024A. According to some embodiments, the gap between spring washer hole and shaft 1024B is in the range of about 0.015 inch to 0.035 inch. Spring washers 1028E can be formed by elastic material. According to some embodiments and as illustrated, spring washers 1028E are Belleville washers formed by spring steel. Although two spring washers 1028E are shown, more or less spring washers can be used. The spring can be arranged in different stacking arrangements, such as in series, in parallel, or in series and in parallel.

[0164] A flat metal washer 1028D is inserted between the uppermost spring washer 1028E and the insulating ring 1028C, with the shaft 1024B extending through a hole formed in the washer 1028D. The washer 1028D is used to distribute the mechanical load of the upper spring washer 1028E to prevent the spring washer 1028E from cutting into the insulating ring 1028C.

[0165] The insulating ring 1028C overlies and abuts the washer 1028D. The insulating ring 1028C has a body ring and a cylindrical upper flange or collar extending upward from the body ring. The hole receives the shaft 1024B. According to some embodiments, the gap between the hole and the shaft 1024B is in the range of about 0.025 inches to 0.065 inches. A peripheral groove that opens upward and outward is formed in the top corner of the body ring.

[0166] The insulating ring 1028C is preferably formed of a dielectric material or an electrically insulating material having a high melting and burning temperature. For example, the insulating ring 1028C may be formed of polycarbonate, ceramic, or a high temperature polymer.

[0167] End cap 1028A overlies and abuts insulating ring 1028C. End cap 1028A has a hole that receives shaft 1024B. According to some embodiments, the gap between the hole and shaft 1024B is in the range of about 0.1 inches to 0.2 inches. For example, end cap 1028A can be formed of aluminum.

[0168] The clip 1028B is resilient and truncated ring-shaped. The clip 1028B is partially received in the groove 1022H and partially extends radially inward from the inner wall of the housing 1022 to limit the axial outward displacement of the end cap 1028A. The clip 1028B may be formed of spring steel.

[0169] O-ring 1030B is positioned in groove 1024G so that it is captured between shaft 1024B and insulating ring 1028C. O-ring 1030A is positioned in a groove in insulating ring 1028C so that it is captured between insulating member 1028C and sidewall 1022B. O-ring 1030C is positioned in groove 1024H to seal with insulating ring 1028C. When installed, O-rings 1030A-1030C are compressed so that they are biased against adjacent interface surfaces and form a seal between adjacent interface surfaces. In an overvoltage or fault event, byproducts (such as hot gases and fragments from thyristors 1046, 1048 or varistors 1042, 1044) can fill or disperse into cavity chamber 1026. The O-rings 1030A- 1030C may confine or prevent these byproducts from exiting the active energy absorber module 1000 through the housing opening 1022D.

[0170] The O-rings 1030A-1030C may be formed of the same or different materials. According to some embodiments, the O-rings 1030A-1030C are formed of a resilient material, such as an elastomer. According to some embodiments, the O-rings 1030A-1030C are formed of rubber. The O-rings 1030A-1030C may be formed of a fluorocarbon rubber, such as VITON® available from DuPont. TM Rubber. Other rubbers, such as butyl rubber, may also be used. According to some embodiments, the rubber has a durometer between about 60 Shore A and 100 Shore A.

[0171] The electrode head 1024A and the housing end wall 1022A are arranged along the load or clamping axis CC ( Fig.16 ) is constantly biased or loaded against the active component subassembly 1040 in the direction F to ensure a secure and uniform engagement between the interfacing contact surfaces specified above. As described below, this aspect of the unit 100 can be understood by considering the method for assembling the unit 100 according to the present invention. In some embodiments, the clamping axis CC is aligned with the axis AA ( Fig.16 ) generally coincide.

[0172] The signal cables 1062A-1062B are secured in the openings of the cable gland 1036. The cable gland 1036 is secured in the line port 1022F (eg, using an adhesive). The cables 1062A-1062B are connected to the terminals 1045F, 1045G.

[0173] Components 1042, 1044, 1046, 1048, 1050, 1052, 1054, 1056, 1058, 1060 are assembled to form active component subassembly 1040 ( Fig.16 ). The subassembly 1040 is placed in the cavity 1022C such that the lower contact surface or portion 1051A of the interconnect member 1056 engages the contact surface 1022G of the end wall 1022A.

[0174] O-rings 1030A-1030C are installed in their corresponding grooves.

[0175] The head 1024A is inserted into the cavity 1022C such that the contact surface 1024C engages the upper contact surface or portion 1051A of the interconnect member 1054 .

[0176] Spring washer 1028E slides down from shaft 1024B. Washer 1028D, insulating ring 1028C, and end cap 1028A slide down from shaft 1024B and cover spring washer 1028E. A clamp (not shown) or other suitable device is used to force end cap 1028A downward, thereby deflecting spring washer 1028E. When end cap 1028A is still under the load of the clamp, clip 1028B is compressed and inserted into groove 1022H. Then, clip 1028B is released and allowed to return to its original diameter, so that clip 1028B partially fills the groove and extends partially from groove 1022H radially inward into the cavity. Thus, clip 1028B and groove 1022H are used to maintain the load on end cap 1028A to partially deflect spring washer 1028E. The end cap 1028A is loaded onto the insulating ring 1028C and the loading from the insulating ring onto the spring washer is in turn transferred to the head 1024 A. In this manner, the subassembly 1040 is sandwiched (clamped) between the head 1024A and the electrode wall 1022A.

[0177] When the active energy absorber module 1000 is assembled, the housing 1022 , electrodes 1024 , insulating members 1028C, end caps 1028A, clips 1028B, O-rings 1030A- 1030C, and cable glands 1036 collectively form a unit housing or housing assembly that houses the components within the chamber 1026 .

[0178] In the assembled active energy absorber module 1000, the large planar contact surfaces of the components 1022A, 1024A, 1042, 1044, 1046, 1048, 1050, 1052, 1054 can ensure reliable and consistent electrical contact and connection between the components during an overvoltage or surge current event. The head 1024A and the end wall 1022A are mechanically loaded against the components to ensure a secure and uniform engagement between the mating contact surfaces.

[0179] Advantageously, the active energy absorber module 1000 incorporates two varistors 1042 , 1044 in the same modular device in an electrically parallel manner so that energy can be shared between the varistors 1042 , 1044 during electrical conduction.

[0180] The design of the active energy absorber module 1000 combines the varistor sheets 1042, 1044 in a single modular unit to provide compressive loading of the thyristors 1046, 1048. The active energy absorber module 1000 provides suitable electrical interconnections between the electrodes 1042, 1044, the thyristors 1046, 1048, and the varistor sheets 1042, 1044, while maintaining a compact form factor and providing appropriate thermal dissipation of energy from the varistors 1042, 1044.

[0181] The construction of the active energy absorber module 1000 provides a safe failure mode for the device. During use, one or more of the varistors 1042, 1044 and the thyristors 1046, 1048 may be damaged due to overheating and arcing may occur within the housing assembly 1021. The housing assembly 1021 can contain the damage (e.g., debris, gas, and immediate heat) within the active energy absorber module 1000, so that the active energy absorber module 1000 fails in a safe manner. In this way, the active energy absorber module 1000 can prevent or reduce any damage to adjacent equipment (e.g., switchgear equipment in the cabin) and harm to people. In this way, the active energy absorber module 1000 can enhance the safety of equipment and people.

[0182] In addition, the active energy absorber module 1000 provides a fault protection mechanism in response to an end-of-life mode in one or more of the varistors 1042, 1044. In the event of a varistor 1042, 1044 failing, a corresponding line (e.g., Figure 6 The varistor conducts fault current between the line 1) and the neutral line. As is well known, a varistor has an inherent standard clamping voltage VNOM (sometimes called the "breakdown voltage" or simply the "varistor voltage") at which the varistor begins to conduct current. Below VNOM, current will not pass through the varistor. Above VNOM, the varistor will conduct current (i.e., leakage current or surge current). The VNOM of a varistor is usually specified as the voltage measured across the varistor with a DC current of 1 mA.

[0183] As is known, a varistor has three operating modes. In the first, normal mode (as discussed above), the varistor is actually an electrical insulator until the nominal voltage is reached. In the second, normal mode (also discussed above), when the varistor is subjected to an overvoltage, the varistor temporarily and reversibly becomes an electrical conductor during the overvoltage condition and returns to the first mode thereafter. In the third mode, the so-called end-of-life mode, the varistor is in fact worn out and becomes a permanent, irreversible electrical conductor.

[0184] A varistor also has an inherent clamping voltage VC (sometimes simply referred to as the "clamping voltage"). The clamping voltage VC is defined as the maximum voltage across the varistor measured when a specified current is applied to the varistor for a period of time according to a standard protocol.

[0185] In the absence of an overvoltage condition, the varistor sheets 1042, 1044 provide a high resistance so that no current flows through the active energy absorber module 1000, as it electrically behaves as an open circuit. That is, generally no current flows through the varistor. If an overcurrent surge event (typically transient; e.g., a lightning strike) or an overvoltage condition or event (typically of longer duration than an overcurrent surge event) exceeds VNOM, the resistance of the varistor decreases rapidly, thereby allowing current to flow through the active energy absorber module 1000 and creating a shunt path for current to flow to protect other components of the associated electrical system. Under normal circumstances, the varistor recovers from these events without significant overheating of the active energy absorber module 1000.

[0186] Varistors have multiple failure modes. The failure modes include: 1) the varistor fails to a short circuit; and 2) the varistor fails to a linear resistor. The failure of a varistor to a short circuit or a linear resistor can be caused by the conduction of a single or multiple surge currents of sufficient magnitude and duration, or a single or multiple consecutive overvoltage events that will drive sufficient current through the varistor.

[0187] A short circuit fault typically appears as a local pinhole or penetration (referred to herein as a "fault site") extending through the thickness of the varistor. The fault site creates a path for current to flow between two electrodes that have a low resistance but high enough to generate ohmic losses and cause overheating of the device even at low fault currents. A sufficiently large fault current passing through the varistor can melt the varistor in the area of ​​the fault site and generate an arc.

[0188] Failure of the varistor to become a linear resistor will result in a limited current being conducted through the varistor, which will result in heat accumulation. This heat accumulation can result in catastrophic heat dissipation, and the device temperature can exceed a specified maximum temperature. For example, the maximum allowable temperature of the outer surface of the device may be set by a code or standard to prevent burning of adjacent components. If the leakage current is not interrupted within a certain period of time, the overheating will eventually cause the varistor to fail as a short circuit as defined above.

[0189] In some cases, even if the varistor fails as a short circuit, the current through the failed varistor may be limited by the power system itself (e.g., ground resistance in the system or in photovoltaic (PV) power applications, where the fault current depends on the power generation capability of the system at the time of the fault), which may result in a gradual increase in temperature. For example, there are cases where a limited leakage current flows through the varistor due to an overvoltage condition that is prolonged in time due to a power system fault. These conditions may result in a temperature increase in the device, such as when the varistor has failed as a linear resistor, and may cause the varistor to fail as a linear resistor or a short circuit as described above. Thyristors may also fail as short circuits in a manner similar to varistors when the energy dissipated in the thyristor exceeds its power dissipation limit, which may be given by the square of the current multiplied by the time (i 2 *t). The difference between the two may be that, at the same level of conducted current, a thyristor may dissipate much less energy if it is properly designed and dimensionalized for the specific application, and therefore is less likely to fail in the first place. However, the failure mode may be very similar to that of an MOV, i.e., failure through a low ohmic resistance path or a pinhole which may produce arcing and / or overheating.

[0190] As discussed above, in some circumstances, the active energy absorber module 1000 may assume an "end of life" mode in which the varistor sheets 1042, 1044 are fully or partially exhausted (i.e., in an "end of life" state), resulting in an end of life fault. When the varistor reaches the end of its useful life, the active energy absorber module 1000 will generally become a short circuit with a very low but non-zero ohmic resistance. As a result, in an end of life condition, a fault current will continue to flow through the varistor even in the absence of an overvoltage condition. In this case, the fusible element 1032 may operate as a fail-safe mechanism that bypasses the failed varistor and creates a permanent low-ohmic short circuit between the terminals of the active energy absorber module 1000 in the manner described in U.S. Patent No. 7,433,169, the disclosure of which is incorporated herein by reference.

[0191] Each thyristor 1046, 1048 may also fail in the same or similar manner as the failure modes described herein for the varistors 1042, 1044, including failing to a short circuit and failing to a linear resistor. The thyristors 1046, 1048 may also exhibit an "end of life" mode as described for the varistors 1042, 1044. The thyristors 1046, 1048 will exhibit behaviors and responses similar or substantially the same as those described for the varistors 1042, 1044. When the failure modes of both the varistors and the thyristors are similar, the same bypass mechanism may be used in the same chamber to enable fail-safe operation of the device 1000 when either the varistors 1042, 1044 or the thyristors 1046, 1048 fail.

[0192] The fusible member 1032 is adapted and configured to operate as a thermal cutout to electrically short the current applied to the associated active energy absorber module 1000 around the varistors 1042, 1044 and thyristors 1046, 1048 to prevent or reduce the generation of heat in the varistors and thyristors. In this manner, the fusible member 1032 can operate as a switch to bypass the varistors 1042, 1044 and thyristors 1046, 1048 and prevent overheating and catastrophic failure as described above. As used herein, the fail-safe system is triggered when a situation occurs that requires the fail-safe system to operate as described to short the electrodes 1022A, 1024A.

[0193] When heated to a threshold temperature, the fusible member 1032 will flow to bridge and electrically connect the electrodes 1022A, 1024A. Thus, the fusible member 1032 diverts the current applied to the active energy absorber module 1000 to bypass the varistors 1042, 1044 and the thyristors 1046, 1048, thereby stopping the current-induced heating of the varistors or thyristors. Thus, the fusible member 1032 can be used to prevent or inhibit heat dissipation (caused by or generated in the varistors 1042, 1044 and / or the thyristors 1046, 1048) without interrupting the current through the active energy absorber module 1000.

[0194] More specifically, the fusible member 1032 initially has Fig.15 and Fig.16 The first configuration shown is such that it does not electrically couple the electrode 1024 and the housing 1022 except through the header 1024A. When a heat accumulation event occurs, the electrode 1024 is heated thereby. The fusible member 1032 is also heated directly and / or by the electrode 1024. During normal operation, the temperature in the fusible member 1032 remains below its melting point, thereby maintaining the fusible member 1032 in a solid form. However, when the temperature of the fusible member 1032 exceeds its melting point, the fusible member 1032 melts (completely or partially) and flows under the action of gravity into a second configuration different from the first configuration. The fusible member 1032 bridges the electrode 1024 to the housing 1022 or shorts the electrode 1024 to bypass the varistors 1042, 1044 and the thyristors 1046, 1048. That is, one or more new direct flow paths are provided from the surface of the electrode 1024 through the fusible member 1032 to the surface of the housing sidewall 1022B. According to some embodiments, at least some of the flow paths do not include varistor sheets 1042 , 1044 or thyristors 1046 , 1048 .

[0195] According to some embodiments, the active energy absorber module 1000 is adapted such that when the fusible member 1032 is triggered to short the active energy absorber module 1000, the conductivity of the active energy absorber module 1000 is at least as great as the conductivity of the feeder cable and the outlet cable connected to the device.

[0196] Reference Fig.17 and Fig.18 , in which an active energy absorber module 1100 according to an alternative embodiment is shown. The active energy absorber module 1100 and Figure 6The active energy absorber module 1100 corresponds to the active energy absorber module 400 of the circuit. The active energy absorber module 1100 is constructed in the same manner as the active energy absorber module 1000, except that the trigger circuit 1102 is integrated within the active energy absorber module 1100 and encapsulated in the closed chamber 1126 of the housing assembly 1121. As a result, the active energy absorber module 1100 can operate as an independent self-triggering device that can be connected between two lines and provide protection against (transient and transient) overvoltage and surge (e.g., lightning) events. Because the trigger circuit 1102 is housed in the housing assembly 1121, the line port 1022F can be eliminated.

[0197] In this case, refer to Fig.17 , the inner electrode 1124 has a two-piece construction including a shaft member 1125 threadedly fixed to a head member 1127. The trigger circuit 1102 is housed in a trigger circuit housing 1170A. The trigger circuit 1102 and the housing 1170A together form a trigger circuit module 1170. The shaft member 1125 extends through the housing 1170A, and the trigger circuit module 1170 is captured between the head 1127 and an integral flange 1125A of the shaft member 1125. A circuit assembly 1162 corresponding to the circuit assembly 1062 electrically connects the trigger circuit 1102 to the thyristor.

[0198] Reference Fig.19 , in which an active energy absorber module 1200 according to an alternative embodiment is shown. The active energy absorber module 1200 is constructed in the same manner as the active energy absorber module 1100 (including a housing assembly 1221 corresponding to the housing assembly 1021 and a trigger circuit module 1270 and a trigger circuit 1202 enclosed in a closed chamber 1226), except that each circuit leg includes three varistor sheets 1242 connected in parallel. For example (when the varistor has the same construction as the varistor), this embodiment can provide a higher power consumption than the active energy absorber module 1100. Fig.17 The active energy absorber module 1000 for higher energy absorption.

[0199] Reference Figure 20-23 , in which an active energy absorber module 1300 according to an alternative embodiment is shown. The active energy absorber module 1300 and Figure 6The active energy absorber module 1300 corresponds to the active energy absorber circuit 400 of the circuit, except that the unit 1300 also integrates the inductor 420 into the active energy absorber module 1300. The active energy absorber module 1300 is constructed in the same manner as the active energy absorber module 1100 (including the housing component 1321 corresponding to the housing component 1121, and the trigger circuit module 1370 and the trigger circuit 1302 encapsulated in the cavity 1326), except that the active energy absorber module 1300 also includes an integrated inductor coil component 1380 encapsulated in the cavity 1326. The coil component 1380 includes Figure 6 The coil 420 of the circuit corresponds to the coil 1381.

[0200] Coil assembly 1380 includes an electrically conductive outer coil member 1382, an electrically conductive inner coil member 1384, an electrically conductive interface plate 1385A, a coupling fastener 1385B, an electrically conductive terminal member or shaft 1386, an electrically insulating plate 1385C, an electrically conductive coupling member 1387, an electrically insulating case 1388, and an electrically insulating outer cover 1389. Coil members 1382, 1384 together form coil 1381.

[0201] The outer coil member 1382 includes a coil body 1382A, a helical extension of the coil band 1382B defining a helical coil passage 1382C, and a coupling extension 1382D. The threaded opening 1382E extends axially through the coil body 1382A. Similarly, the inner coil member 1384 includes a coil body 1384A, a helical extension of the coil band 1384B defining a helical coil passage 1384C, and a coupling extension 1384D. The threaded opening 1384E extends axially through the coil body 1384A.

[0202] Interface plate 1385A is inserted between coupling extensions 1382D, 1384D, and the three components are secured together by fasteners 1385B. Insulating plate 1385C is sandwiched between coil members 1382, 1384 to prevent or inhibit current from flowing directly therebetween.

[0203] Box body 1388 comprises outer shell part 1388A, inner partition wall part 1388B, and outer partition wall part 1388C. Outer shell part 1389 partially surrounds and encloses parts 1388A-1388C. Outer partition wall part 1388C fills coil passage 1382C between adjacent windings of coil band 1382B. Inner partition wall part 1388B fills coil passage 1384C between adjacent windings of coil band 1384B. Cover 1389 fits and is sleeved on box body 1388.

[0204] The terminal shaft 1386 is mechanically fixed and electrically connected in the opening 1382E and protrudes through the post hole 1388D in the box body 1388 and above the box body 1388.

[0205] The coupling member 1387 is mechanically fixed and electrically connected in the opening 1384E and protrudes through the post hole in the cover 1389. The coupling member 1387 is also mechanically fixed and electrically fixed in the opening of the head 1327.

[0206] Components 1382, 1384, 1385A, 1386, 1387 are formed of metal, and, in some embodiments, aluminum. According to some embodiments, each coil member 1382, 1384 is monolithic, and in some embodiments, unitary.

[0207] The box body 1388 can be formed of a dielectric material or an electrically insulating material having a high melting and burning temperature. In some embodiments, the box body 1388 is formed of a polymeric material. In some embodiments, the box body 1388 includes an epoxy resin. In some embodiments, the box body 1388 includes a material selected from the group consisting of an epoxy resin adhesive and / or an epoxy casting resin or a silicone elastomer. In some embodiments, the box body 1388 is monolithic. In some embodiments, the box body 1388 includes a material selected from the group consisting of an epoxy resin adhesive and / or an epoxy casting resin that is itself covered by an outer layer of a different material.

[0208] The outer case layer 1389 may be formed of a different material than the case 1388 to provide complementary properties. In some embodiments, the outer case layer 1389 is formed of a material that provides enhanced corrosion resistance compared to the material of the case 1388. In some embodiments, the outer case layer 1389 is formed of a silicon compound or PBT.

[0209] In use, current flows sequentially through the terminal shaft 1386 , the outer winding strip 1382B, the coupling extension 1382D, the interface plate 1385A, the coupling extension 1384D, the inner winding strip 1384B, the coupling member 1387 , and the head 1327 .

[0210] By axially stacking the sequentially arranged coil strips 1382B, 1384B, the outer diameter of the active energy absorber module 1300 may be reduced.

[0211] In addition to the above advantages, the electrical protection device according to the embodiments of the present invention can also provide a number of advantages. The device can be formed so as to have a relatively compact form factor. The device can be capable of being retrofitted to be installed in an appropriate location of a similar type of surge protection device that does not have a circuit as described herein. Specifically, the device can have the same length dimensions as the aforementioned such device.

[0212] According to some embodiments, the junction area between each of the electrode contact surface, the varistor contact surface, and the thyristor contact surface is at least one square inch respectively.

[0213] According to some embodiments, the bias electrodes (eg, electrodes 1022 and 1024 ) apply a load along axis CC to the varistors and thyristors in the range of 2000 lbf to 26000 lbf depending on their surface areas.

[0214] According to some embodiments, the combined thermal mass of the housing (e.g., housing 1022) and the electrode (e.g., electrode 1024) is substantially greater than the thermal mass of each of the varistor and thyristor trapped therebetween. As used herein, the term "thermal mass" means the product of the specific heat of one or more materials of an object and one or more masses of the one or more materials of the object. That is, thermal mass is the amount of energy required to raise 1 gram of one or more materials of the object by 1 degree Celsius multiplied by the one or more masses of the one or more materials in the object. According to some embodiments, the thermal mass of any one of the electrode head and the electrode wall is substantially greater than the thermal mass of the varistor or thyristor. According to some embodiments, the thermal mass of at least one of the electrode head and the electrode wall is at least twice the thermal mass of the varistor or thyristor, and, according to some embodiments, is at least 10 times greater. According to some embodiments, the combined thermal mass of the head and the electrode wall is substantially greater than the thermal mass of the varistor or thyristor, according to some embodiments, is at least twice the thermal mass of the varistor or thyristor, and, according to some embodiments, is at least 10 times greater. According to some embodiments, the combined thermal mass of the head and the electrode wall is substantially greater than the thermal mass of the varistor or thyristor, according to some embodiments, is at least twice the thermal mass of the varistor or thyristor, and, according to some embodiments, is at least 10 times greater.

[0215] As discussed above, spring washer 1028E is a Belleville washer. Belleville washers can be used to apply relatively high loads without requiring substantial axial space. However, other types of biasing devices may be used in addition to or in place of one or more Belleville washers. Suitable alternative biasing devices include one or more coil springs, wave washers, or spiral washers.

[0216] Reference Fig.24 and Fig.25 , in which an active energy absorber system 1401 including a trigger circuit 1402 and an active energy absorber module 1400 according to an alternative embodiment is shown. The active energy absorber module 1400 and Figure 31400, except that the trigger circuit 110 is external to the unit 1400. The active energy absorber module 1400 is constructed in the same manner as the active energy absorber module 1000 (including the trigger circuit 1402 external to the housing assembly 1421), except that the active component subassembly 1440 of the active energy absorber module 1400 is constructed in a different manner than the active component subassembly 1040 of the active energy absorber module 1000.

[0217] The active component subassembly 1440 includes a varistor sheet 1442, two thyristors 1446, 1448, two contact plates 1450, 1452, an insulating member (layer or plate) 1460, and two interconnection members 1454, 1456 stacked axially between the electrode head 1424A and the electrode wall 1422A in the chamber 1421. The varistor 1442 corresponds to the varistor 106, the thyristor 1446 corresponds to the thyristor 102, the thyristor 1448 corresponds to the thyristor 104, and the trigger circuit 1402 corresponds to the trigger circuit 110. The trigger circuit 1402 is connected to the active component subassembly 1440 by the wiring assembly 1462. The interconnection members 1454, 1456, the contact plates 1450, 1452 are arranged in accordance with Figure 3 The manner shown electrically interconnects the varistor 1442, the thyristors 1446, 1448, and the trigger circuit 1402. As discussed above, the thyristors 1446, 1448 are each arranged in an electrically anti-parallel configuration.

[0218] Now refer to Fig.26 , Fig.26 1 is a schematic block diagram illustrating an apparatus for active overvoltage protection according to some embodiments of the present invention. An active energy absorber 1600 may be connected between power lines 70, 72 in a power distribution system and / or component. Power lines 70, 72 may include power lines and / or neutral lines in a single-phase power system or phase lines and / or neutral lines in a multi-phase system (e.g., a three-phase power system). Thus, the active energy absorber 1600 may be connected between two phase lines or power lines and / or between a phase line or power line and a neutral line.

[0219] Some embodiments provide that the active energy absorber 1600 can selectively conduct fault current in response to an overvoltage condition. For example, some embodiments provide that when the active energy absorber 1600 is in a conduction mode, the overvoltage condition can be clamped to a specific voltage by absorbing energy corresponding to an overvoltage fault condition that exceeds a clamping voltage. Some embodiments are directed to providing protection for transient overvoltage conditions originating from a power system that can persist for a longer period of time than transient and / or surge voltages.

[0220] In some embodiments, the active energy absorber 1600 may include the same Figure 3 The trigger circuit 1610 discussed above is similar to the trigger circuit 110. As such, additional description thereof will be omitted.

[0221] The active energy absorber 1600 may include a first thyristor 1604 including a first anode connected to the first power line 70, a first cathode, and a first gate level. The active energy absorber 1600 may include a second thyristor 1602 including a second anode connected to the second power line 72, a second cathode connected to the cathode of the first thyristor 1604, and a second gate level. In this regard, the first thyristor 1604 and the second thyristor 1602 are connected in series with each other in opposite directions relative to each other.

[0222] The active energy absorber 1600 may include a first varistor 1606 connected to an anode of the first thyristor 1604 and a second varistor 1608 connected to an anode of the second thyristor 1602 and the first varistor 1606. In this regard, the first varistor 1606 and the second varistor 1608 may be connected in series with each other. In this regard, the anode of the first thyristor 1604 and the first varistor 1606 may each be connected to the first power line 70, and the anode of the second thyristor 1602 and the second varistor 1608 may each be connected to the second power line 72.

[0223] Some embodiments provide that a first inductor 1620 may optionally be used to reduce the di / dt through the thyristors 1602, 1604 when the thyristors 1602, 1604 are conducting surge current. Some embodiments provide that the power lines 70, 72 themselves have sufficient inductance due to the length of the power lines 70, 72, the size of the cables, and any transformers installed upstream of the device. However, adding the inductor 1620 between the power line 70 and the device results in an increase in the level of protection (clamping voltage) that the device will experience during surge events and transient overvoltages. In this regard, if the inductance of the power system is insufficient, additional plug-in modules may be added to increase the total inductance of the power line. Some embodiments provide that since two varistors are used in the same device, energy absorption may be shared between the two varistors during conduction.

[0224] In some embodiments, the active energy absorber 1600 includes a second inductor 1622 that can be connected between the cathodes of the first and second thyristors 1604, 1602 and the common terminal of the first and second thyristors 1604, 1602. The second inductor 1622 can protect the first and second thyristors 1604, 1602 from experiencing excessive current change rates (e.g., di / dt). For example, in the case of a surge event from line 170 to line 272, the voltage across the first varistor 1606 can rise very quickly, for example, exceeding the dV / dt of the first thyristor 1604. Then, after a certain period of time, the first thyristor 1604 can self-trigger. Because this does not happen immediately (depending on the internal construction of the first and second thyristors 1604, 1602 and the internal parasitic capacitance between the anode and the gate stage), if a delay occurs, the surge current through the first varistor 1606 will reach a certain value when the first thyristor 1604 self-triggers. The second inductor 1622 can prevent the current through the first thyristor 1604 from rising momentarily and thereby preventing the rate of change of the current flowing therethrough from being exceeded. Some embodiments provide that a small inductance value of the second inductor 1622 can be sufficient to slow down the surge current conversion and protect the first thyristor 1604 from damage. In some embodiments, the value of the second inductor 1622 can be in the range of 1 μH to 10 μH, however, such a range is not limiting.

[0225] In some embodiments, the circuitry of active energy absorber 1600 may include SPD functionality. As such, some embodiments provide that active energy absorber 1600 may be used without an additional and / or external SPD.

[0226] In addition, during surge events and transient overvoltages, due to the internal parasitic capacitance between the gate level and the anode of the thyristors 1602, 1604 and between the gate level and the cathode, they can be self-triggered. According to convention, in order to avoid the self-triggering of the thyristors 1602, 1604 during surge events and transient overvoltage events, the manufacturer can make the parasitic capacitance as low as possible. However, when the current is applied, the parasitic capacitance will be higher, which can improve the convenience of manufacturing. In this regard, the device can show improved triggering sensitivity during surge events and transient overvoltage events. In this way, before the thyristors 1602, 1604 are triggered and the voltage is clamped at the protection level of the varistors 1606, 1608, the voltage will not reach a very high value. In this regard, whether the event is a transient overvoltage, a surge current or a transient overvoltage, the device can be uniformly clamped at the voltage level of a single varistor 1606, 1608.

[0227] The active energy absorber 1600 may not use a snubber circuit because it can avoid false triggering of the thyristors due to high dV / dt during surge events or transient overvoltages. Instead, the self-triggering capability of the thyristors 1602, 1604 can clamp the voltage across a single varistor.

[0228] Additionally, the device may provide an independent self-triggering operation that may be connected between two lines in a power system and provide protection against transient overvoltages, instantaneous overvoltages, and / or surge / lightning currents.

[0229] Reference Fig. 27 and Fig.28 , in which an active energy absorber module 1700 according to an alternative embodiment is shown. The active energy absorber module 1700 and Fig.26 The active energy absorber module 1700 corresponds to the active energy absorber module 1600 of the circuit. The active energy absorber module 1700 is configured in accordance with the active energy absorber module 1100 ( Fig.17 ) except as discussed below.

[0230] Module 1700 includes a trigger circuit module 1770, which is connected to trigger circuit module 1170 ( Fig.17 ) corresponds to and includes trigger circuit 1610 ( Fig.26 ) corresponding to the trigger circuit.

[0231] Module 1700 includes an active component subassembly 1740 disposed in closed chamber 1726 between housing electrode end wall 1722A and electrode head 1727. Active component subassembly 1740 includes two varistors 1742, 1744, two thyristors 1746, 1748, two contact plates 1750, 1752, an insulator 1760, and three interconnect members 1754, 1756, 1758, which correspond to components 1042, 1044, 1046, 1048, 1050, 1052, 1060, 1054, 1056, and 1058 of module 1000. The components of subassembly 1740 are connected as follows: Fig.26 The portion of the circuit corresponding to or forming Fig.26 The circuit of the present invention is as follows: the varistor 1742 corresponds to the varistor 1606; the varistor 1744 corresponds to the varistor 1608; the thyristor 1746 corresponds to the thyristor 1602; and the thyristor 1748 corresponds to the thyristor 1604. The interconnection members 1754, 1756, 1758 and the contact plates 1750, 1752 are arranged in accordance with Fig.26 The manner shown electrically interconnects the varistors 1742, 1744 and the thyristors 1746, 1748.

[0232] Subassembly 1740 also includes a coil assembly 1780, an additional interconnect member 1759, and two additional electrical insulation layers 1763, 1765. Coil assembly 1780 and Fig.26 The coil 1622 corresponds to and Fig.26 The manner shown is electrically connected to other components by interconnect member 1759.

[0233] Reference Fig.28 , coil assembly 1780 includes an upper contact plate 1782, a lower contact plate 1784, a coil member 1786, an interface member 1787, a fastener 1788, and two coil insulators 1789. Components 1782, 1784, 1786, 1787 are formed of an electrically conductive material, such as a metal (eg, aluminum).

[0234] Coil member 1786 includes coil body 1786A, helically extending coil band 1786B defining helical coil channel 1786C, and coupling extension 1786D. Coil member 1786 is electrically connected to upper contact plate 1782 via coupling extension 1786D and to lower contact plate 1784 via coil body 1786A. Coil band 1786B is electrically isolated from contact plates 1782, 1784 by insulator 1789.

[0235] The interconnection member 1759 includes a first contact portion 1759A that contacts the lower surface of the lower coil assembly contact plate 1784 and the anode of the upper thyristor 1746. The interconnection member 1759 also includes a second contact portion 1759B that contacts the interconnection member 1758 and the anode of the lower thyristor 1748. The interconnection member 1759 includes a bridge portion 1759C (at Fig. 27 1759A and 1759B are electrically connected, and thus the above-mentioned components are electrically connected.

[0236] Signal cables 1762A, 1762B corresponding to the signal cables 1062A, 1062B extend from the trigger circuit module 1770. Each cable 1762A, 1762B includes a gate-level line 1762GA, 1762GB and a reference line 1762RA, 1762RB. The gate-level lines 1762GA, 1762GB are electrically terminated at the control terminals 1745F of the thyristors 1746, 1748 through gate-level connectors 1762D. The reference lines 1762RA, 1762RB are mechanically terminated and electrically connected (e.g., by welding) to the bridge portions 1757B of the interconnect members 1754 and 1756, respectively. In this manner, reference line 1762RA is electrically connected to the cathode of thyristor 1746 through interconnect member 1754 and contact plate 1750 , and reference line 1762RB is electrically connected to the cathode of thyristor 1748 through interconnect member 1756 and contact plate 1752 .

[0237] Fig.29 An active energy absorber module 1800 is shown according to a further embodiment. Active energy absorber module 1800 is constructed in the same manner as module 1700, except that module 1800 does not have an internal trigger circuit module corresponding to trigger circuit module 1770 but instead employs an external trigger circuit as described above for module 1000.

[0238] Reference Fig.30 , in which an active energy absorber module 1900 according to another embodiment is shown. The module 1900 and Figure 4 The active energy absorber module 201 corresponds to the module 1900. Fig. 27 ) are constructed in substantially the same manner, except as follows.

[0239] Module 1900 includes an active component subassembly 1940 enclosed in closed chamber 1926 between housing electrode end wall 1922A and electrode head 1927. Subassembly 1940 includes Figure 4 The MOV 206 corresponds to the variable resistor 1942, and Figure 4 The thyristors 202 and 204 corresponding to the thyristors 1946, 1948, and Figure 4 The inductor coil 1986 corresponding to the inductance 208 and Figure 4 The trigger circuit 210 corresponds to the trigger circuit module 1970.

[0240] Interconnect members 1954, 1956 and contact plates 1950, 1952 are Figure 41942, thyristors 1946, 1948, coil 1986, and electrodes 1922A, 1927 are electrically interconnected in the manner shown in FIG. 1950. Electrical insulator 1960 electrically isolates interconnect member 1956 from interconnect member 1954. The trigger circuit of module 1970 is similar to that described above for module 1700 ( Fig. 27 ) are electrically connected to the gate terminals and cathodes of thyristors 1946, 1948 by gate-level lines 1962A, 1962GB and reference lines 1962RA, 1962RB via gate-level connector 1962D and interconnect members 1954, 1956.

[0241] Now refer to Fig.31 , Fig.31 2 is a schematic block diagram illustrating an apparatus for active overvoltage protection according to some embodiments of the present invention. The active energy absorber 2000 may be connected between power lines 70, 72 in a power distribution system and / or component. The power lines 70, 72 may include power lines and / or neutral lines in a single-phase power system or phase lines and / or neutral lines in a multi-phase system (e.g., a three-phase power system). Therefore, the active energy absorber 2000 may be connected between two phase lines or power lines and / or between a phase line or power line and a neutral line.

[0242] Some embodiments provide that the active energy absorber 2000 can selectively conduct fault current in response to an overvoltage condition. For example, some embodiments provide that when the active energy absorber 2000 is in a conduction mode, the overvoltage condition can be clamped to a specific voltage by absorbing energy corresponding to an overvoltage fault condition that exceeds a clamping voltage. Some embodiments are directed to providing protection for transient overvoltage conditions originating from a power system that can last longer than transient and / or surge voltages.

[0243] In some embodiments, the active energy absorber 2000 includes a Figure 3 The trigger circuit 110 discussed above is similar to the trigger circuit 2010. As such, further description thereof will be omitted.

[0244] The active energy absorber 2000 may include a first thyristor 2002 including a first anode, a first cathode, and a first gate level. The active energy absorber 2000 may include a second thyristor 2004 including a second anode connected to the first cathode of the first thyristor 2002, a second cathode connected to the first anode of the first thyristor 2002, and a second gate level. In this regard, the first thyristor 2002 and the second thyristor 2004 are connected in anti-parallel to each other.

[0245] The active energy absorber 2000 may include a first varistor 2006 and a second varistor 2008. The first varistor 2006 may be connected between the first power line 70 and the second varistor 2008. The second varistor 2008 may be connected between the first varistor 2006 and the second power line 72. In this regard, the first varistor 2006 and the second varistor 2008 may be connected in series with each other.

[0246] Some embodiments provide that an inductor 2022 may optionally be used to reduce the di / dt through the thyristors 2002, 2004 when the thyristors 2002, 2004 are conducting surge currents. Some embodiments provide that the power lines 70, 72 themselves have sufficient inductance due to the length of the power lines 70, 72, the size of the cables, and any transformers installed upstream of the device. However, the inductor 2022 may be connected between the connection node of the first and second thyristors 2006, 2008 and the connection node corresponding to the first cathode of the first thyristor 2002 and the second anode of the second thyristor 2004. The first anode of the first thyristor 2002 and the second cathode of the second thyristor 2004 may be connected to a terminal of the second varistor 2008, which is connected to the second power line 72.

[0247] In some embodiments, the circuitry of active energy absorber 2000 may include SPD functionality. As such, some embodiments provide that active energy absorber 1600 may be used without an additional and / or external SPD.

[0248] In addition, during surge events and transient overvoltages, due to the internal parasitic capacitance of the thyristors 2002, 2004 between the gate level and the anode and between the gate level and the cathode, the thyristors 2002, 2004 can be self-triggered. According to convention, in order to avoid the thyristors 2002, 2004 from self-triggered during surge events and transient overvoltage events, the manufacturer will make the parasitic capacitance as low as possible. However, when the current is applied, the parasitic capacitance will be higher, which can improve the convenience of manufacturing. In this regard, the device can exhibit improved triggering sensitivity during surge events and transient overvoltage events. In this way, before the thyristors 2002, 2004 are triggered and the voltage is clamped to the protection level of the varistors 2006, 2008, the voltage will not reach a very high value. In this regard, whether the event is a transient overvoltage, a surge current or a transient overvoltage, the device can be consistently clamped at the voltage level of a single varistor 2006, 2008.

[0249] During surge events or transient overvoltages due to high dV / dt, the active energy absorber 2000 may not use a snubber circuit because it can avoid false triggering of the thyristors. Instead, the self-triggering capability of the thyristors 2002, 2004 can clamp the voltage across a single varistor.

[0250] Additionally, the device may provide an independent self-triggering operation that may be connected between two lines in a power system and provide protection against transient overvoltages, instantaneous overvoltages, and / or surge / lightning currents.

[0251] Reference Fig.32 , in which an active energy absorber module 2100 according to another embodiment is shown. The module 2100 and Fig.31 The active energy absorber module 2000 corresponds to the module 2100. The module 2100 is in accordance with the module 1900 ( Fig.30 ) are constructed in substantially the same manner, except as follows.

[0252] Module 2100 includes an active component subassembly 2140 enclosed in closed chamber 2126 between housing electrode end wall 2122A and electrode head 2127. Subassembly 2140 includes Fig.31 A variable resistor 2142 corresponding to the variable resistor 2006, a variable resistor 2144 corresponding to the variable resistor 2008, a thyristor 2146 corresponding to the thyristor 2002, a second thyristor 2148 corresponding to the thyristor 2004, an inductor coil 2148 corresponding to the inductor 2022, and a trigger circuit module 2170 corresponding to the trigger circuit 2010.

[0253] The interconnecting members 2154, 2156, 2158, 2159 and the contact plates 2050, 2052 are arranged in accordance with Fig.31 The varistors 2142, 2144, thyristors 2146, 2148, coil 2186, and electrodes 2122A, 2127 are electrically interconnected in the manner shown. Two electrical insulators 2160 electrically isolate interconnect members 2154 and 2156 from each other and interconnect members 2156 and 2158 from each other. The trigger circuit of trigger circuit module 2170 is as described above for module 170 ( Fig. 27 ) is electrically connected to the gate terminals and cathodes of the thyristors 2146, 2148 by gate-level lines 2162GA, 2162GB and reference lines 2162RA, 2162RB via gate-level connectors 2162D and interconnection members 2158, 2159.

[0254] Without departing from the spirit and scope of the present invention, in view of the benefits of the present disclosure, a person of ordinary skill in the art may make many changes and modifications. Therefore, it must be understood that the illustrated embodiments have only been stated for the purpose of example, and should not be considered to limit the present invention defined by the appended claims. Therefore, the appended claims will be interpreted as not only including the combination of elements stated literally, but also including all equivalent elements for performing substantially the same function in substantially the same manner to obtain substantially the same result. Therefore, the claims are understood to include the content specifically illustrated and described above, the content equivalent in concept, and the content including the essential conception of the present invention.

Claims

1. An overvoltage protection device, comprising: a first electrode member; a second electrode member; as well as a plurality of varistor sheets, each of the plurality of varistor sheets being formed of a varistor material; as well as at least one electrically conductive interconnect member connecting the varistor sheet in electrical parallel between the first electrode member and the second electrode member; Wherein, the varistor sheet and the at least one interconnection member are axially stacked between the first electrode and the second electrode.

2. The overvoltage protection device according to claim 1, wherein: The plurality of varistor sheets include a first varistor sheet, a second varistor sheet, and a third varistor sheet; and The at least one interconnect member includes at least a first interconnect member and a second interconnect member connecting the varistor sheet in electrical parallel between the first electrode member and the second electrode member.

3. The overvoltage protection device according to claim 1, wherein: Each varistor sheet includes opposing planar contact surfaces; Each interconnect member includes two spaced apart planar contact portions and a bridge portion extending between and electrically connecting the contact portions; and The contact portion engages the planar contact surface.

4. The overvoltage protection device according to claim 1, wherein: The first electrode comprises a shell electrode including an end wall and an integral side wall that together define a cavity; the second electrode extends into the cavity; and The varistor sheet and the at least one interconnect member are disposed in the cavity.

5. The overvoltage protection device according to claim 4, wherein: The housing electrode is formed of a metal monolith.

6. The overvoltage protection device of claim 1, comprising a biasing device that applies an axial compressive load to the varistor sheet and the at least one interconnect member.

7. The overvoltage protection device of claim 1, comprising an electrically conductive fusible member, wherein: The fusible member melts in response to heat in the overvoltage protection device and forms an electrical short circuit path across the first and second electrode members.

8. The overvoltage protection device according to claim 1, wherein: The varistor assembly includes an insulator sheet axially inserted and stacked between at least two of the interconnect members.

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