Electrical protection device group with two stages connected in series

Abstract

The invention relates to a group of electrical protection devices with two stages connected in series, the first stage comprising a circuit breaker called first or upstream circuit breaker, the second stage comprising one or more circuit breakers called second or downstream circuit breakers in parallel with each other. It is characterized in that the tripping mechanism of the upstream circuit breaker does not comprise a instantaneous protection member, but first a first tripping chain which makes it possible to adjust a long delay tripping curve of inverse time and a short delay tripping curve with no tripping time, secondly a second tripping chain comprising a member capable of discriminating between the light between 300 and 450 nm by eliminating the visible and infrared light to eliminate the light specific to the gas jet emitted by the one or more circuit breakers called downstream circuit breakers during the switching operation, and simultaneously measuring the current level and the maximum threshold of the light emitted at the busbar, the second tripping chain being capable of tripping the upstream circuit breaker when the current exceeds a predetermined value and the emitted light exceeds a predetermined threshold of the emitted light.

Description

Technical Field

[0001] This invention relates to a two-stage electrical protection device group having a series connection. The first stage includes a circuit breaker referred to as a first circuit breaker or upstream circuit breaker, and the second stage includes one or more circuit breakers referred to as second circuit breakers or downstream circuit breakers connected in parallel with each other. The rating of the one or more downstream circuit breakers is lower than that of the first circuit breaker. Each circuit breaker, for each phase, includes: a switch block on which two separable contacts are placed and through which a current line for a sensor for measuring current passes; a component for manually or remotely actuating the contacts; a component for automatically opening the contacts controlled by a tripping mechanism controlled by the aforementioned current sensor; and a component for adjusting a long-delay tripping curve with inverse time and a short-delay tripping curve with non-tripping time. The tripping mechanism of the one or more so-called second circuit breakers also includes a so-called instantaneous protection component that allows the tripping mechanism associated with the one or more so-called second circuit breakers to be actuated when the current reaches a so-called instantaneous tripping DIN threshold of the one or more second circuit breakers. Background Technology

[0002] Such electrical protection devices are known to enable the simultaneous performance of three functions: extreme switching performance achieved by cascading between two low-voltage switchgear stages, total selectivity between the two stages, and ultra-fast protection of the upper stage in the event of an intermediate fault between the two stages.

[0003] However, these three functions are difficult to be compatible with the performance levels that systems of low-voltage switchgear must achieve, which are primarily used in marine auxiliary switchboards with high power (typically above 100KA and 690V) at low voltage.

[0004] Generally, cascading and selective technologies are incompatible with high current values ​​above 525V.

[0005] This invention addresses these problems and proposes a low-voltage electrical protection device group designed for very high-power low-voltage applications, in order to simultaneously provide ultimate switching performance, total selectivity, and ultra-fast protection of the upper stage in the event of an intermediate fault between two stages, achieved through cascading. Summary of the Invention

[0006] Therefore, one subject of the present invention is a two-stage electrical protection device group of the type described above, characterized in that the tripping mechanism for the upstream circuit breaker does not include so-called instantaneous protection components, but instead includes a first tripping chain and a second tripping chain. The first tripping chain allows adjustment of a long-delay tripping curve with inverse time and a short-delay tripping curve with no tripping time. The second tripping chain includes an optical sensor capable of distinguishing light between 300 and 450 nm by eliminating visible and infrared light to eliminate light characteristic of gas jets emitted by one or more circuit breakers, referred to as downstream circuit breakers, during switching operations, and components for simultaneously measuring the current level and a maximum threshold for the light emitted at the bus. The second tripping chain enables the upstream circuit breaker to trip when the current exceeds a predetermined value and the emitted light exceeds a predetermined threshold for the emitted light.

[0007] According to a specific feature, the tripping mechanism or each tripping mechanism includes a long-delay tripping curve for adjusting currents with an inverse time limit for values ​​substantially less than 10 times the nominal current In, and a short-delay tripping curve for adjusting currents with a non-tripping time of 20 ms for values ​​between 1.5 and 10 times the nominal current.

[0008] According to another characteristic, the circuit breaker is a limiting circuit breaker.

[0009] According to another feature, the aforementioned predetermined current value and threshold are 10 times the nominal current In and 8000 lux, respectively.

[0010] According to another characteristic, the rating of the limiting circuit breaker referred to as the first circuit breaker is between 800 and 1000A, while the rating of one or more limiting circuit breakers referred to as the second circuit breaker is between 40 and 250A.

[0011] According to another feature, the circuit breaker referred to as the first circuit breaker has a rated value of 800A, while the circuit breaker referred to as the second circuit breaker has a rated value of 100A.

[0012] According to another feature, the instantaneous tripping threshold S of one or more second circuit breakers is approximately 11 kArms.

[0013] According to another feature, the aforementioned upstream circuit breaker includes a pyrotechnic propellant that allows for ultra-fast tripping in the event of a spark discharge fault between phases in the region between the two stages.

[0014] According to another feature, the aforementioned optical sensor includes a discrimination fiber comprising fibers made of fluoride glass, the ends of which are treated to block waves longer than 450 nm.

[0015] Another subject of the invention is an electrical equipment group with two levels, characterized in that it is used for auxiliary switchboards on ships with power exceeding 100KA / 690V.

[0016] However, other advantages and features of the invention will become clearer from the following detailed description with reference to the accompanying drawings, which are given by way of example only, wherein: Attached Figure Description

[0017] Figure 1 An electrical schematic diagram of a two-stage low-voltage electrical equipment assembly according to the prior art is shown;

[0018] Figure 2 A block diagram of an electronic circuit breaker belonging to the equipment group according to the prior art is shown;

[0019] Figure 3 A graph illustrating two tripping curves is shown, which correspond to the tripping curves of two circuit breakers located upstream and downstream of the device group according to the aforementioned prior art;

[0020] Figure 4 An electrical schematic diagram of a low-voltage electrical equipment assembly according to a specific embodiment of the present invention is shown;

[0021] Figure 5 A block diagram of an electronic circuit breaker belonging to a group of devices according to a specific embodiment of the present invention is shown; and

[0022] Figure 6 The diagram illustrates two tripping curves, which correspond to the tripping curves of two circuit breakers located upstream and downstream of the equipment group according to the foregoing embodiments of the present invention. Detailed Implementation

[0023] exist Figure 1 In the present invention, one can see a low-voltage electrical equipment group E or equipment system comprising two series-connected stages a and b, according to existing technology.

[0024] Group E includes a limiting circuit breaker 1, referred to as the upstream circuit breaker or the first circuit breaker, which is advantageously rated at 800A, and as... Figure 2As shown, the limiting circuit breaker 1 includes a switching block 2 containing a mechanism 3 for switching the contacts of the circuit breaker, a mechanism 4 for manually or remotely actuating the contacts of the circuit breaker, an electromagnetic coil type tripping mechanism 5, a current sensor for each phase 6, an electronic tripping mechanism 7 that allows for inverse-time long-delay tripping curve regulation for currents (advantageously) less than 10 times the nominal current In and for currents (advantageously) between 1.5 and 10 times the nominal current In with short-delay tripping curve having no tripping time (advantageously, 20 ms) and is integrated into the circuit breaker with a fixed threshold (advantageously) (11kA rms) instantaneous protection component.

[0025] This equipment group E also includes one or more limiting circuit breakers, referred to as downstream circuit breakers or second circuit breakers 8, which are connected in parallel with each other and are connected in series with the aforementioned upstream limiting circuit breaker 1.

[0026] These one or more so-called downstream limiting circuit breakers 8 are rated (advantageously) between 40A and 250A, and include, in the same manner as one or more upstream circuit breakers, limiting switch sections, manual or remote actuation mechanisms, tripping mechanisms containing electromagnetic coils, current sensors for each phase, electronic tripping mechanisms, and integrated transient protection components with a non-adjustable fixed threshold advantageously 3000A.

[0027] The following will refer to Figures 1 to 3 Describe the operation of this circuit breaker according to the prior art.

[0028] exist Figure 3 The graph illustrates two tripping curves, c and d, for the upstream and downstream circuit breakers. The y-axis represents the tripping time T in seconds, and the x-axis represents the current in amperes flowing through the circuit on which the circuit breaker group is placed.

[0029] First, we will consider Figure 1 The fault occurs at position 1 (i.e., downstream of the so-called second circuit breaker 8).

[0030] like Figure 3 As shown, in zone X, the current through the device is below the DIN threshold of the first circuit breaker 1. Due to the time selectivity caused by the 20ms delay associated with the first circuit breaker 1 (which causes the second circuit breaker 8 to trip first), only the second circuit breaker 8 trips.

[0031] In region Y, the current value is higher than the DIN threshold, i.e., higher than the instantaneous tripping threshold S of the first circuit breaker 1; both circuit breakers 1 and 8 trip; cascading occurs when the switching performance is higher than the maximum switching performance of the second circuit breaker 8. Because the upstream circuit breaker 1 has already tripped, there is no selectivity.

[0032] It can be recalled that selectivity is the coordination between automatic switching devices so that a fault occurring at any point on the network can be cleared by the circuit breaker placed immediately upstream of the fault, and only by that circuit breaker.

[0033] Cascading is a technique that enhances the switching capacity of a circuit breaker by coordinating with another protection device placed upstream.

[0034] Now we will consider the case where a high short-circuit fault occurs at location 2 (i.e., downstream of the first circuit breaker 1 and upstream of the second circuit breaker 8).

[0035] In this configuration, the so-called first limiting circuit breaker 1 limits the current by disconnecting its contacts, and its tripping is activated once the current value exceeds the DIN threshold of the instantaneous tripping mechanism. The trip coil is activated, its control mechanism opens, and the opening of the main contacts is confirmed.

[0036] Figure 4 A device group F according to a specific embodiment of the present invention is shown.

[0037] Similar to the prior art, the device assembly according to the invention includes a first limiting circuit breaker 1, referred to as an upstream circuit breaker, and one or more so-called second circuit breakers or downstream circuit breakers 8 connected in parallel with each other, the one or more so-called second circuit breakers 8 being placed in series with respect to the first circuit breaker 1.

[0038] One or more second circuit breakers 8 are constructed in the same manner as in the prior art.

[0039] like Figure 5 As shown more specifically in the diagram, the upstream circuit breaker 1 according to the invention, in addition to the elements already present in the upstream circuit breaker according to the prior art, also includes an identification optical sensor 9 capable of controlling an additional control unit 10. This unit 10 is capable of receiving information from the current measurement sensor 6 belonging to the switch block 2 on the one hand, and on the other hand, controlling the tripping mechanism to open the coil 5 for the contacts of the so-called first circuit breaker 1.

[0040] Therefore, by means of the above-mentioned technical means, the tripping mechanism of the first circuit breaker 1 differs from the tripping mechanism of the prior art in that it is decomposed into a first tripping chain and a second tripping chain. The first tripping chain includes components for regulating a long-delay tripping curve with an inverse time for currents less than 10 times the nominal current In, and components for regulating a short-delay tripping curve with a non-tripping time (advantageously 20 ms) for currents 1.5 to 10 times the nominal current. This first tripping chain does not include integrated instantaneous protection components with a fixed threshold.

[0041] The second trip chain includes components for simultaneously measuring the current level and the maximum threshold of light emitted by optical sensor 6, which distinguishes light between 300 and 450 nm by eliminating visible and infrared light so as to disregard light emitted by the electric arc on the bus and eliminate light characteristic of the gas jet emitted by the low-voltage circuit breaker during switching.

[0042] The following will refer to Figures 4 to 6 Describe the operation of this equipment group.

[0043] First, we will consider the scenario where a fault occurs at position 1 (i.e., downstream of the so-called second circuit breaker 8), such as... Figure 4 As shown.

[0044] In such Figure 6 In the region X defined in the diagram, only the second circuit breaker 8 trips when the current value is below the DIN threshold S of the first limiting circuit breaker 1; as with the prior art, there is time selectivity.

[0045] In region Y, the current value exceeds the DIN threshold S of the first limiting circuit breaker 1. In this case, only the second circuit breaker 8 trips. In the same manner as in the prior art, cascading occurs when the switching performance exceeds the maximum switching performance of the second circuit breaker 8, aided by the disconnection of the contacts of the switching block 2 of the first circuit breaker 1.

[0046] In this situation, there is selectivity between the two circuit breakers because the first circuit breaker 1 has not yet tripped. This is partly because the first circuit breaker 1 does not include a so-called instantaneous tripping component, and partly because the optical sensor 9 has eliminated the light generated by the escape of the breaking gas from the downstream circuit breaker 8. Specifically, due to this elimination, the second tripping chain of the upstream circuit breaker 1 does not cause the upstream circuit breaker 1 to trip because the optical measurement value performed by the additional control unit 10 does not exceed the threshold.

[0047] Specifically, when a fault occurs downstream of the second circuit breaker 8, the circuit breaker, upon interrupting the current, emits visible and infrared light corresponding to wavelengths greater than 450 nm via an ionized gas jet escaping from its outlet. If the optical sensor is active for these wavelength values, selectivity cannot be guaranteed. By activating the optical sensor 9 and current measurement, the first circuit breaker 1 will be opened.

[0048] The inspection will now be conducted at Figure 4A high short-circuit fault occurs at position 2 (i.e., downstream of the first circuit breaker 1 and upstream of the second circuit breaker 8). In this case, the first limiting circuit breaker 1 limits the current by disconnecting, and when the current exceeds 8000 lux and the current value is higher than a predetermined value (e.g., 10In, i.e., 10 times the nominal current), the first trip chain of its trip mechanism 7 is activated. The coil of the main actuator is activated, its control mechanism opens, and the opening of the main contacts is confirmed. The circuit breaker has a self-protection function in the event of a fault.

[0049] It should be noted that, since the second circuit breaker 8 is a limiting device, its electrodynamic withstand capability is low (approximately 15 times the nominal current). This is crucial for it to assist the switch as quickly as possible during switching operations with a performance level exceeding that of the downstream circuit breaker, which is also a limiting circuit breaker, that can withstand alone.

[0050] Therefore, switching energy can be distributed between the two circuit breakers 1 and 8 connected in series.

[0051] The instantaneous trip threshold S is fixed at a value slightly lower than the electric withstand capability to ensure the circuit breaker's self-protection. When the current exceeds the electric withstand capability, it must trip instantaneously, for example, within 10ms.

[0052] It should be noted that, according to another embodiment, the downstream limiting circuit breaker 8 may be a circuit breaker based on magnetocaloric technology without electronic components.

[0053] It should also be noted that the optical sensor 9 will be advantageously coupled to the pyrotechnic propellant, which will only function in the event of an interphase spark failure in the region between the two stages.

[0054] Therefore, according to the present invention, the upstream limiting circuit breaker 1 is equipped with a double trip chain. The first trip chain provides protection against overload current reaching 10 times the nominal current, which is approximately IN for an 800A circuit breaker. For the "instantaneous" value, the delay is 20ms, which is longer than the switching time of the downstream circuit breaker 8 at a performance level of 12kA RMS. The second trip chain is activated by current measurements above 10In and optical measurements from optical sensors with blocking wavelengths greater than 450nm, as these wavelengths are characteristic of the gas jets emitted by the low-voltage circuit breaker during switching.

[0055] With this dual trip chain, when a fault occurs at position 1, on the one hand, the cascading between the two low-voltage switchgear stages, through the coordination of the two switch groups, achieves ultimate switching performance; on the other hand, the total selectivity between the two stages is obtained, characterized by the upstream circuit breaker not tripping.

[0056] For a fault occurring at position 2, ultra-fast protection is achieved for the upstream and associated busbars via the second trip chain.

[0057] This is achieved by better absorbing and distributing switching energy between the two stages, resulting in a significantly noticeable external performance.

[0058] In order to obtain ultra-fast protection during an internal fault between the two stages of the facility, the upstream circuit breaker 1 may be advantageously equipped with a pyrotechnic propellant that only functions in the event of a spark fault between phases in the region between the two stages.

[0059] It should be noted that in the case of so-called "V-shaped" switchboards, such as Figure 4 As shown, only one discrimination optical sensor is needed. The discrimination optical sensor will be positioned relative to the upstream circuit breaker at the height of the downstream device (with a lower rating) connected to the upstream equipment and its connected vertical busbar. Specifically, if an electric arc occurs on the vertical busbar, the electrodynamic force will push the arc away from the transformer.

[0060] It should be noted that the identification optical sensor can be replaced by identification fiber, that is, a fiber made of fluoride glass with its ends treated to block waves with wavelengths exceeding 450 nm.

[0061] This invention is advantageously applied to low-voltage switchgear systems, primarily for marine auxiliary switchboards with high power outputs (typically above 100kA, 690V) at low voltage. Specifically, for critical facilities such as those on ships, ensuring selectivity between different loads is crucial. A failure on one load should not cause other loads to malfunction.

[0062] However, the present invention can be advantageously applied to all fields that require this level of simultaneous cascading and selective performance, such as in the field of renewable energy, where increasingly higher performance levels are required.

[0063] The system comprises two stages connected in series, enabling the simultaneous provision of three functions that are difficult to achieve at this performance level: extreme switching performance achieved through cascading between the two device stages, total selectivity between the two stages, and ultra-fast protection of the upper stage in the event of an intermediate fault between the two stages.

[0064] Of course, the present invention is not limited to the embodiments described and illustrated, which are given by way of example only.

[0065] Conversely, the present invention includes all technical equivalents of the described components and combinations thereof implemented in accordance with the spirit of the invention.

Claims

1. A group of electrical protection devices having two stages connected in series, the first stage comprising a circuit breaker called upstream breaker, the second stage comprising one or more circuit breakers called downstream breakers connected in parallel to each other, the one or more downstream breakers having a lower rating than the upstream breaker, each circuit breaker comprising for each phase: A switch block on which two separable contacts and a current line for a sensor for measuring the current pass through, means for manually or by remote control actuating the contacts, means for automatically opening the contacts controlled by a tripping mechanism controlled by the aforementioned current sensor and comprising means for adjusting a long delay tripping curve of the inverse time and a short delay tripping curve with no tripping time, the tripping mechanism of one or more so-called downstream breakers also comprising instantaneous protection means which allow the tripping mechanism associated with these one or more downstream breakers to be actuated when the current reaches the instantaneous tripping DIN threshold of these one or more downstream breakers, characterized in that, The tripping mechanism (7) of the upstream breaker (1) does not comprise the so-called instantaneous protection means, but firstly a first tripping chain which makes it possible to adjust a long delay tripping curve of the inverse time and a short delay tripping curve with no tripping time, and secondly a second tripping chain comprising an optical sensor (9) capable of discriminating between the light between 300 and 450 nm by eliminating the visible light and the infrared light to eliminate the light specific to the gas jets emitted during the switching operation by one or more breakers called downstream breakers (8) and means for simultaneously measuring the current level and the maximum threshold of the light emitted at the busbar, the second tripping chain being capable of tripping the upstream breaker (1) when the current exceeds a predetermined value and the emitted light exceeds a predetermined threshold of the emitted light.

2. The group of electrical protection devices according to claim 1, characterized in that, Said tripping mechanism (7) of said upstream breaker (1) comprises means for adjusting a long delay tripping curve of the inverse time for a current substantially less than 10 times the nominal current In and means for adjusting a short delay tripping curve with no tripping time of 20 ms for a current between 1.5 and 10 times the nominal current.

3. The set of electrical protection devices according to claim 1 or 2, characterized in that, Said upstream breaker (1) and said downstream breakers (8) are limiting breakers.

4. The group of electrical protection devices according to claim 3, characterized in that, Said predetermined value and said predetermined threshold are respectively 10 times the nominal current In and 8000 lux.

5. The group of electrical protection devices according to claim 3, characterized in that, The rating of the limiting breakers called upstream breakers (1) is between 800 and 1000 A, while the rating of the one or more limiting breakers called downstream breakers (8) is between 40 and 250 A.

6. The set of electrical protection devices according to claim 1 or 2, characterized in that, The rating of the breakers called upstream breakers (1) is 800 A, while the rating of the breakers called downstream breakers (8) is 100 A.

7. The set of electrical protection devices according to claim 1 or 2, characterized in that, The value of the instantaneous tripping DIN threshold of said one or more downstream breakers (8) is 11 kArms.

8. The set of electrical protection devices according to claim 1 or 2, characterized in that, Said upstream breaker (1) comprises a pyrotechnic propellant for allowing an ultrafast tripping in the event of a spark discharge fault between phases in the area located between the two stages.

9. The set of electrical protection devices according to claim 1 or 2, characterized in that, Said optical sensor (9) comprises a discriminating optical fiber comprising a fiber made of fluoride glass, the ends of which are treated for blocking the waves longer than 450 nm.

10. The set of electrical protection devices according to claim 1 or 2, characterized in that, It is used for ship auxiliary power distribution panels with power higher than 100 KA / 690 V.

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