Transformer direct current magnetic bias treatment device

Abstract

The utility model provides a direct-current magnetic bias treatment device for a transformer, and relates to the technical field of transformer protection. The transformer direct current magnetic bias treatment device comprises a blocking protection circuit and a direct current magnetic bias monitoring circuit, and the blocking protection circuit comprises a blocking capacitor connected with a neutral point of a transformer in series and a bypass protection circuit connected with the blocking capacitor in parallel. The bypass protection circuit comprises a discharge gap module and a high-energy zinc oxide module, the discharge gap module comprises a current transformer and a second voltage limiting protector, the current transformer is connected in series with the second voltage limiting protector, and the neutral point of the transformer is conducted and grounded through a series branch of the second voltage limiting protector and the current transformer; the discharge gap module further comprises a vacuum trigger, the vacuum trigger is connected between the neutral point of the transformer and the ground, and the current transformer transmits signals to the switch controller to control the vacuum trigger to be turned on or turned off. The device solves the problem that a running transformer generates direct current magnetic bias due to direct current flowing through a transformer winding.

Description

Technical Field

[0001] The utility model relates to the technical field of transformer protection, in particular to a transformer direct current magnetic bias treatment device. Background Art

[0002] The DC transmission system has been developing rapidly in modern times due to its advantages of long transmission distance, large transmission capacity and low loss. However, when the DC transmission line is under commissioning and maintenance or when a fault occurs, it will operate in a single-pole loop mode. At this time, the earth acts as a return circuit, and a DC current of up to several thousand amperes may flow through it. The electric field distribution near the DC grounding electrode is greatly increased due to the current flowing through it, and a higher surface potential appears near the grounding electrode. As the distance increases, the surface potential gradually decreases.

[0003] Due to the different ground potentials at different locations, in the AC power grid in this area, a DC current will flow from the grounded neutral point into the transformer and then flow to distant places through the transmission line. The DC current flowing through the transformer winding causes the operating transformer to produce DC bias magnetism, which has an adverse effect on the safe operation of the transformer itself and the AC power grid.

[0004] Existing DC bias magnetic treatment devices generally solve the problem of DC bias magnetic treatment by installing a high-energy zinc oxide module. However, in actual application, the high-energy zinc oxide module may have abnormal parameters and protection failure, so the reliability of the device cannot be fully taken into account by simply installing a high-energy zinc oxide module. Utility Model Content

[0005] In view of the deficiencies in the prior art, the present invention aims to provide a transformer DC bias control device to protect the transformer itself and the safety of the AC power grid.

[0006] The purpose of this disclosure can be achieved through the following technical solutions:

[0007] A transformer DC bias control device comprises a DC blocking protection circuit and a DC bias monitoring circuit, wherein the DC blocking protection circuit comprises a DC blocking capacitor connected in series with the neutral point of the transformer and a bypass protection circuit connected in parallel with the DC blocking capacitor, wherein the bypass protection circuit comprises a discharge gap module and a high-energy zinc oxide module, wherein the discharge gap module is connected in parallel with the high-energy zinc oxide module;

[0008] The discharge gap module comprises a current transformer and a second voltage limiting protector, the input end of the current transformer is connected to the neutral point of the transformer, the current transformer is connected in series with the second voltage limiting protector, and the neutral point of the transformer is connected to ground through the second voltage limiting protector and the current transformer series branch;

[0009] The conduction value of the second voltage limiting protector is less than or equal to the conduction value of the first voltage limiting protector;

[0010] The discharge gap module further includes a vacuum trigger connected between the neutral point of the transformer and the ground. The current transformer transmits a signal to a switch controller, and the switch controller controls the vacuum trigger to be turned on or off based on the current signal transmitted by the current transformer.

[0011] Preferably, the DC bias magnetic monitoring circuit includes a current acquisition device, which is used to measure the DC current of the neutral point of the transformer and to collect the mark current value between the DC blocking capacitor and the ground wire;

[0012] The DC bias magnetic monitoring circuit also includes a digital monitoring device, which is used to receive the current value collected by the current collection device and perform data exchange with the background.

[0013] Preferably, the high-energy zinc oxide module includes a first voltage limiting protector and a fuse, and the second voltage limiting protector is connected in series with the fuse.

[0014] Preferably, the current collection device includes a front cover and a rear cover of the box, the front cover and the rear cover of the box are detachably connected, the front end of the rear cover of the box is provided with a groove, a grounding bar is engaged in the groove, the middle part of the grounding bar is sleeved with an open-and-closed type mutual inductor fixed in the rear cover of the box, a controller is installed on the inner side of the rear cover of the box, and two cable pipes are installed on the bottom, the controller is provided with an ammeter, a microprocessor, and a wireless signal transmitter and receiver, the microprocessor is electrically connected to the ammeter and the wireless signal transmitter and receiver, respectively, the ammeter is electrically connected to the open-and-closed type mutual inductor, and a clamp is installed on the back of the rear cover of the box.

[0015] Preferably, a heater is installed in the front cover of the box, and the heater is electrically connected to the microprocessor.

[0016] Preferably, the upper and lower ends of one side of the rear cover of the box body are fixedly installed with connecting sleeves, the upper and lower ends of one side of the front cover of the box body are fixedly connected with connecting shafts, and the two connecting shafts are rotatably connected to the two connecting sleeves respectively.

[0017] Preferably, a fixing seat is fixedly mounted on the other side surface of the rear cover of the box body, a slot is provided on the surface of the fixing seat, and a limiting groove is provided on the top wall of the slot;

[0018] An adjustment frame is fixedly installed on the other side surface of the front cover of the box body, an adjustment slot is provided in the adjustment frame, an insertion rod is installed in the adjustment slot, the insertion rod can slide up and down in the vertical direction in the adjustment slot, the top of the extended end of the insertion rod is fixedly connected to a limit rod, a spring is fixedly connected between the bottom of the adjustment slot and the insertion rod, the spring is always in a compressed state, a sliding hole is provided at the top of the adjustment slot, a button is fixedly connected to the top of the limit rod, the button extends out of the adjustment slot from the sliding hole, and the button is slidably connected to the sliding hole.

[0019] Preferably, the digital monitoring device comprises a main control module and a display module electrically connected to the main control module, the main control module is electrically connected to the controller, the main control module is an FPGA+PLC integrated chip, and the display module is a display.

[0020] The nouns, conjunctions or adjectives involved in the above technical solution are explained as follows:

[0021] Sliding connection means that two objects are in contact but not fixed, and they can slide relative to each other;

[0022] A fixed connection means that there can be no relative movement between the connecting parts.

[0023] Beneficial effects of the present disclosure:

[0024] The present application provides a transformer DC bias magnetic treatment device. When a three-phase unbalanced fault occurs in the system and other protections fail, the transformer neutral point voltage and short-circuit current will continue to increase. When the neutral point voltage exceeds the conduction value of the high-voltage zinc oxide valve plate FR2, the transformer neutral point is connected to the ground through the high-voltage zinc oxide valve plate FR2 and the current transformer CT series branch. A high voltage is instantly generated on the secondary side of the current transformer CT to trigger a vacuum trigger. The discharge circuit is turned on to quickly ground the fault short-circuit current, thereby achieving the purpose of backup protection and preventing the fault from expanding and damaging the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the circuit schematic diagram of the utility model transformer DC bias magnetic treatment device;

[0026] Figure 2 This is the circuit schematic diagram of the discharge gap module of the utility model;

[0027] Figure 3 This is the principle diagram of the circuit current acquisition device and digital monitoring device of the utility model;

[0028] Figure 4 This is a schematic diagram of the structure of the circuit current acquisition device of the utility model;

[0029] Figure 5 It is a schematic diagram of the connection structure between the adjustment frame and the fixing seat of the utility model.

[0030] Among them, 100, column; 110, grounding bar; 200, rear cover of the box; 210, cable duct; 220, controller; 230, clamp; 240, connecting sleeve; 250, fixing seat; 251, slot; 252, limit slot; 300, open and close type mutual inductor; 400, front cover of the box; 410, heater; 420, connecting shaft; 430, adjustment frame; 431, adjustment slot; 432, sliding hole; 440, plug rod; 441, limit rod; 442, button; 443, spring. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0032] The utility model discloses a transformer direct current magnetic bias treatment device.

[0033] Example:

[0034] Please refer to Figure 1 A transformer DC bias control device includes a DC isolation protection circuit and a DC bias monitoring circuit, wherein the DC isolation protection circuit includes a DC isolation capacitor C and a bypass protection circuit connected in parallel with the DC isolation capacitor, the bypass protection circuit includes a discharge gap module and a high-energy zinc oxide module, the discharge gap module is connected in parallel with the high-energy zinc oxide module, and the DC isolation capacitor C is connected in series to the neutral point of the transformer, that is, in series between the neutral line of the transformer and the ground line.

[0035] The high-energy zinc oxide module includes a first voltage limiting protector. When a single-phase grounding asymmetric short circuit occurs in the transformer, the impact current flows through the DC blocking capacitor C, causing the voltage on the DC blocking capacitor C to rise rapidly, triggering the high-voltage zinc oxide to conduct, thereby limiting the voltage across the DC blocking capacitor C and protecting the DC blocking capacitor C.

[0036] The high-energy zinc oxide module also includes a fuse. When a circuit fails or is abnormal, the current continues to increase. When the current exceeds the specified value, the heat generated by the fuse itself causes the fuse to melt, thereby disconnecting the circuit and protecting the DC blocking capacitor C in the circuit.

[0037] There is a maintenance isolating knife GN2 connected in series between the neutral line and the ground line of the transformer, and there is also a startup isolating knife GN1 connected in series between the DC isolation capacitor C and the neutral line of the transformer. There is a locking connection between the maintenance isolating knife GN2 and the startup isolating knife GN1, and they cannot be opened at the same time. When the maintenance isolating knife GN2 is closed, the DC isolation device is in the exit / maintenance state; when the startup isolating knife GN1 is closed, the DC isolation device is in the startup / operation state.

[0038] See also Figure 2 The discharge gap module includes a current transformer CT and a second voltage-limiting protector. The input end of the current transformer CT is connected to the neutral point of the transformer. The current transformer CT is connected in series with the second voltage-limiting protector. The neutral point of the transformer is connected to the ground through the second voltage-limiting protector and the current transformer CT series branch. The discharge gap module also includes a vacuum trigger TR. The vacuum trigger TR is connected between the neutral point of the transformer and the ground. The current transformer CT transmits the signal to the switch controller. The switch controller controls the vacuum trigger TR to open or close based on the current signal transmitted by the current transformer CT. When a three-phase unbalanced fault occurs in the system and the other protections fail, the neutral point voltage and short-circuit current of the transformer will continue to increase. When the short-circuit current exceeds 2kA and the neutral point voltage exceeds the conduction value of the high-voltage zinc oxide valve piece FR2, the neutral point of the transformer is connected to the ground through the high-voltage zinc oxide valve piece FR2 and the current transformer CT series branch. The secondary side of the current transformer instantly generates a high voltage trigger vacuum trigger (trigger voltage ≥ 3000V), and the discharge circuit is turned on to quickly ground the fault short-circuit current, achieving the purpose of backup protection and preventing the fault from expanding and damaging the equipment.

[0039] The first voltage limiting protector and the second voltage limiting protector are respectively high voltage zinc oxide FR1 and high voltage zinc oxide FR2.

[0040] The function of a fuse is to protect the current. The fuse is composed of a fusible element and a fusible tube, and is connected in series in the circuit as a metal conductor. When the current exceeds a certain value, the fuse will generate heat to melt the fusible element, thereby disconnecting the current and achieving a protective effect.

[0041] Specifically, when the transformer DC bias magnetic treatment device operates normally, the capacitor is connected in series to the neutral point of the transformer to play the role of AC isolation, and the remaining bypass in the DC isolation circuit is in an open circuit state;

[0042] When a single-phase grounding or asymmetric short circuit fault occurs in the system, the impact current flows through the DC blocking capacitor C, causing the voltage on the DC blocking capacitor to rise rapidly, triggering the high-energy zinc oxide module to turn on and limit the voltage across the capacitor, thus protecting the DC blocking capacitor.

[0043] When the high-energy zinc oxide module parameter abnormality protection fails, the discharge gap module is triggered to conduct to protect the zinc oxide and capacitors, and the system quickly enters the transformer neutral point direct grounding operation state from capacitor grounding.

[0044] See also Figure 3 The transformer DC bias magnetic treatment device also includes a DC bias magnetic monitoring circuit, and the DC bias magnetic monitoring circuit includes a current acquisition device, and the current acquisition device is used to measure the DC current of the transformer neutral point and collect the mark current value between the DC blocking capacitor and the ground wire;

[0045] The DC bias magnetic monitoring circuit also includes a digital monitoring device, which is used to receive the current value collected by the current collection device and exchange data with the background.

[0046] Optionally, in the implementation of the present application, the current collection device may be diversified, wherein the current collection device may be a conventional current collection device, or may be a current collection device that is further optimized and improved in the embodiments of the present application.

[0047] See also Figure 4 , further optimized and improved, the current collection device includes a box front cover 400 and a box rear cover 200, the box front cover 400 and the box rear cover 200 are detachably connected, a groove is provided at the front end of the box rear cover 200, a grounding bar 110 is clamped in the groove, and an open-and-closed mutual inductor 300 fixed in the box rear cover 200 is sleeved in the middle of the grounding bar 110, a controller 220 is installed on the inner side of the box rear cover 200, and two cable pipes 210 are installed at the bottom, an ammeter, a microprocessor, and a wireless signal transmitter and receiver are provided in the controller 220, the microprocessor is electrically connected to the ammeter and the wireless signal transmitter and receiver respectively, the ammeter is electrically connected to the open-and-closed mutual inductor 300, a clamp 230 is installed on the back of the box rear cover 200, the clamp 230 is clamped on the column 100, and the grounding bar 110 is fixed to the surface of the column 100.

[0048] In order to facilitate the control of the temperature in the box, a heater 410 is installed in the front cover 400 of the box, and the heater 410 is electrically connected to the microprocessor.

[0049] See also Figure 4-5 In order to realize the detachable connection between the box rear cover 200 and the box front cover 400, the upper and lower ends of one side of the box rear cover 200 are fixedly installed with connecting sleeves 240, and the upper and lower ends of one side of the box front cover 400 are fixedly connected with connecting shafts 420, and the two connecting shafts 420 are rotatably connected to the two connecting sleeves 240 respectively.

[0050] In order to facilitate the fixing and disassembly between the box front cover 400 and the box rear cover 200, a fixing seat 250 is fixedly installed on the other side surface of the box rear cover 200, and a slot 251 is opened on the surface of the fixing seat 250, and a limiting groove 252 is opened on the top wall of the slot 251;

[0051] An adjustment frame 430 is fixedly installed on the other side surface of the front cover 400 of the box body, and an adjustment slot 431 is opened in the adjustment frame 430. An insertion rod 440 is installed in the adjustment slot 431. The insertion rod 440 can slide up and down in the vertical direction in the adjustment slot 431. The top of the extended end of the insertion rod 440 is fixedly connected with a limit rod 441, and a spring 443 is fixedly connected between the bottom of the adjustment slot 431 and the insertion rod 440. The spring 443 is always in a compressed state. A sliding hole 432 is opened in the top of the adjustment slot 431, and a button 442 is fixedly connected to the top of the limit rod 441. The button 442 extends out of the adjustment slot 431 from the sliding hole 432, and the button 442 is slidably connected to the sliding hole 432.

[0052] The digital monitoring device includes a main control module and a display module electrically connected to the main control module. The main control module is electrically connected to the controller 220. The main control module is an FPGA+PLC integrated chip, and the display module is a display.

[0053] The current acquisition device adopts an open-and-close current sensor, which is convenient for installation and maintenance. There is no need to disconnect the grounding bus 110 during maintenance, and there is no impact on system safety. The device has a self-protection function. When a system short circuit occurs, it automatically protects the sensor from damage by large current impulses. The device can be equipped with optional three-axis vibration sensors, temperature sensors and noise sensors to monitor the vibration amplitude, frequency, temperature and noise of the transformer. The software of the device improves the temperature characteristics of the sensor according to the temperature correction data.

[0054] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

Claims

1. A transformer DC bias control device, characterized in that: It includes a DC isolation protection circuit and a DC bias magnetic monitoring circuit, wherein the DC isolation protection circuit includes a DC isolation capacitor connected in series with the neutral point of the transformer and a bypass protection circuit connected in parallel with the DC isolation capacitor, wherein the bypass protection circuit includes a discharge gap module and a high-energy zinc oxide module, wherein the discharge gap module is connected in parallel with the high-energy zinc oxide module; The discharge gap module comprises a current transformer and a second voltage limiting protector, the input end of the current transformer is connected to the neutral point of the transformer, the current transformer is connected in series with the second voltage limiting protector, and the neutral point of the transformer is connected to ground through the second voltage limiting protector and the current transformer series branch; The conduction value of the second voltage limiting protector is less than or equal to the conduction value of the first voltage limiting protector; The discharge gap module further includes a vacuum trigger connected between the neutral point of the transformer and the ground. The current transformer transmits a signal to a switch controller, and the switch controller controls the vacuum trigger to be turned on or off based on the current signal transmitted by the current transformer.

2. A transformer DC bias treatment device according to claim 1, characterized in that: The DC bias magnetic monitoring circuit includes a current acquisition device, which is used to measure the DC current of the neutral point of the transformer and to collect the mark current value between the DC blocking capacitor and the ground wire; The DC bias magnetic monitoring circuit also includes a digital monitoring device, which is used to receive the current value collected by the current collection device and perform data exchange with the background.

3. A transformer DC bias treatment device according to claim 1, characterized in that: The high-energy zinc oxide module comprises a first voltage-limiting protector and a fuse, and the second voltage-limiting protector is connected in series with the fuse.

4. A transformer DC bias treatment device according to claim 2, characterized in that: The current collection device includes a front cover and a rear cover of the box, the front cover and the rear cover of the box are detachably connected, a groove is provided at the front end of the rear cover of the box, a grounding bar is clamped in the groove, an open-and-closed mutual inductor fixed in the rear cover of the box is sleeved in the middle of the grounding bar, a controller is installed on the inner side of the rear cover of the box, and two cable pipes are installed on the bottom, an ammeter, a microprocessor, and a wireless signal transmitter and receiver are provided in the controller, the microprocessor is electrically connected to the ammeter and the wireless signal transmitter and receiver respectively, the ammeter is electrically connected to the open-and-closed mutual inductor, and a clamp is installed on the back of the rear cover of the box.

5. A transformer DC bias treatment device according to claim 4, characterized in that: A heater is installed in the front cover of the box body, and the heater is electrically connected to the microprocessor.

6. A transformer DC bias treatment device according to claim 4, characterized in that: The upper and lower ends of one side of the box body rear cover are fixedly installed with connecting sleeves, and the upper and lower ends of one side of the box body front cover are fixedly connected with connecting shafts, and the two connecting shafts are rotatably connected with the two connecting sleeves respectively.

7. A transformer DC bias treatment device according to claim 6, characterized in that: A fixing seat is fixedly mounted on the other side surface of the rear cover of the box body, a slot is provided on the surface of the fixing seat, and a limiting groove is provided on the top wall of the slot; An adjustment frame is fixedly installed on the other side surface of the front cover of the box body, an adjustment slot is provided in the adjustment frame, an insertion rod is installed in the adjustment slot, the insertion rod can slide up and down in the vertical direction in the adjustment slot, the top of the extended end of the insertion rod is fixedly connected to a limit rod, a spring is fixedly connected between the bottom of the adjustment slot and the insertion rod, the spring is always in a compressed state, a sliding hole is provided at the top of the adjustment slot, a button is fixedly connected to the top of the limit rod, the button extends out of the adjustment slot from the sliding hole, and the button is slidably connected to the sliding hole.

8. A transformer DC bias treatment device according to claim 7, characterized in that: The digital monitoring device comprises a main control module and a display module electrically connected to the main control module, the main control module is electrically connected to the controller, the main control module is an FPGA+PLC integrated chip, and the display module is a display.

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