A full compensation device and method using a stepless adjustment arc suppression coil

Abstract

The present invention discloses a full compensation device and method using a stepless regulating arc extinguishing coil, wherein the full compensation device comprises a grounding transformer, a stepless regulating arc extinguishing coil, an adjusting mechanism and a full compensation part, wherein the grounding transformer is connected to the system bus, the stepless regulating arc extinguishing coil is connected in series between the neutral point of the grounding transformer and the ground, the adjusting mechanism is connected to the stepless regulating arc extinguishing coil, and the full compensation part is connected to the controlled end of the stepless regulating arc extinguishing coil, and is used to adjust the inductive reactance of the stepless regulating arc extinguishing coil XH when the system is operating normally, and can fully compensate the system when a single-phase grounding fault occurs in the system. The present invention can cooperate with the stepless regulating arc extinguishing coil to perform system compensation, and the output voltage of the full compensation device is adjusted to the expected amplitude and phase by gradually adjusting the full compensation output voltage and the inductive reactance value of the stepless regulating arc extinguishing coil, thereby achieving full compensation of the grounding voltage and the grounding current, and the adjustment process has no step difference.

Description

Technical Field

[0001] The invention relates to the technical field of single-phase grounding protection of distribution network, in particular to a full compensation device and method based on a stepless regulation arc suppression coil. Background Art

[0002] In the distribution network system, the ground fault active full compensation device is used to compensate for the remaining system reactive current to ground, system active current to ground and harmonic current to ground after compensation by the arc suppression coil when a single-phase ground fault occurs in the system. The traditional ground fault active full compensation device consists of a power transformer, a step-up transformer, a vacuum contactor, an active power compensator and a controller. The controller calculates the compensation value based on the collected electrical quantities, and can compensate the voltage and current of the single-phase ground fault point to near zero by controlling the vacuum contactor and the active power compensator, thereby completely eliminating the arc when a single-phase ground fault occurs. It can also use the disturbance method to accurately select the line, which is the best solution to solve the single-phase ground fault.

[0003] In general, the rated current of a full compensation device is relatively small, with a maximum of about ten amperes, while the grounding current is usually large. Therefore, it needs to be coordinated with a turn-adjusting arc suppression coil. The turn-adjusting arc suppression coil compensates for most of the system's reactive current to ground, and the full compensation device then compensates for the remaining reactive current, active current and harmonic current.

[0004] At present, in addition to the turn-adjustable arc extinguishing coil, there are also stepless adjustable arc extinguishing coils, such as the air gap adjustable arc extinguishing coil, the phase-controlled arc extinguishing coil, the bias magnetic arc extinguishing coil and the magnetically controlled arc extinguishing coil. The advantage of this type of arc extinguishing coil is that there is no step difference and the reactive current of the system can be compensated to zero. Therefore, it is widely used in power systems. However, when this type of stepless adjustable arc extinguishing coil is used in conjunction with a full compensation device for system compensation, there are the following problems: 1) Since this type of arc extinguishing coil performs output compensation after grounding, and the full compensation device also performs compensation after grounding, if the stepless adjustable arc extinguishing coil and the full compensation device are used together, there will be a problem that the stepless adjustable arc extinguishing coil has not been adjusted into place when the full compensation device outputs, which will lead to the overcurrent protection problem of the full compensation device; even if the stepless adjustable arc extinguishing coil uses the reactance value pre-adjusted before grounding and waits for the system to be grounded, there will be a situation where the output voltage of the full compensation device is higher than the neutral point voltage, resulting in the stepless adjustable arc extinguishing coil not being adjusted in time. The full compensation overcurrent protection is in place; 2) For the system with adjustable arc suppression coil, if it is combined with the full compensation device, there will be two controllers, one for controlling the adjustable arc suppression coil and the other for controlling the active power compensator, which will easily cause the problem of uncoordinated compensation; 3) When the arc suppression coil controller is used to control the stepless arc suppression coil to adjust the impedance value, the arc suppression coil actuator is directly controlled by the wire or the serial communication is used to control the arc suppression coil actuator for gear adjustment. The full compensation controller and the active power compensator also use the serial port for communication. This will cause greater interference when the system is running, and the reliability of the transmission of the collected electrical quantities cannot be guaranteed. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a full compensation device and method using a stepless adjustable arc extinguishing coil, which can adjust the output voltage of the full compensation device to the expected amplitude and phase after the system grounding occurs, thereby achieving full compensation for the grounding voltage and grounding current.

[0006] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows.

[0007] A full compensation device using a stepless regulating arc extinguishing coil comprises a grounding transformer connected to a system bus, a stepless regulating arc extinguishing coil is connected in series between the neutral point of the grounding transformer and the ground, and a regulating mechanism is connected to the controlled end of the stepless regulating arc extinguishing coil; the controlled end of the stepless regulating arc extinguishing coil is connected to a full compensation part for compensating the system when a single-phase grounding fault occurs in the system, the full compensation part comprises an active power compensator, a controller and a step-up transformer, the step-up transformer is connected between the neutral point of the grounding transformer and the ground, the active power compensator is connected in parallel to the secondary side of the step-up transformer, and the controller is respectively connected to the controlled ends of the active power compensator and the regulating mechanism.

[0008] The above-mentioned full compensation device uses a stepless adjustable arc extinguishing coil, and the stepless adjustable arc extinguishing coil is an air gap adjustable arc extinguishing coil, a phase-controlled arc extinguishing coil, a bias magnetic arc extinguishing coil or a magnetically controlled arc extinguishing coil.

[0009] In the above-mentioned full compensation device using a stepless adjustable arc extinguishing coil, the controller communicates with the source power compensator and the regulating mechanism respectively via optical fibers.

[0010] In the above-mentioned full compensation device using a stepless adjustable arc suppression coil, a high-voltage switch is connected in series between the neutral point of the step-up transformer and the grounding transformer, and the controlled end of the high-voltage switch is connected to the output end of the controller.

[0011] A full compensation method using a stepless arc extinguishing coil. When a single-phase grounding occurs in the system, a controller calculates the expected voltage that an active power compensator needs to output according to the system grounding condition; secondly, the active power compensator is controlled to be connected to the grid according to the amplitude and phase of the voltage at both ends of the stepless arc extinguishing coil; after the active power compensator is connected to the grid, the controller adjusts the inductive reactance of the stepless arc extinguishing coil through an adjustment mechanism until the output current of the active power compensator is minimum; then, the active power compensator is controlled through optical fiber to adjust the output voltage of the active power compensator to the expected voltage through step-by-step adjustment according to the issued instructions.

[0012] In the above-mentioned full compensation method using a stepless adjustable arc extinguishing coil, the adjustment of the output voltage of the active power compensator includes amplitude adjustment and phase adjustment.

[0013] Due to the adoption of the above technical scheme, the technical progress achieved by the present invention is as follows.

[0014] The present invention can cooperate with a stepless arc extinguishing coil to perform system compensation. The output voltage of the full compensation device is adjusted to the expected amplitude and phase by gradually adjusting the full compensation output voltage and the stepless adjustment of the inductive reactance value of the arc extinguishing coil, thereby achieving full compensation for the grounding voltage and the grounding current, and the adjustment process has no step difference. Moreover, the reactive current component to the ground is adjusted to zero by the stepless adjustment of the arc extinguishing coil, so that the reactive current output by the active power compensator can be close to zero, thereby effectively reducing the active power loss of the active power compensator.

[0015] The stepless arc extinguishing coil and the active power compensator of the present invention are regulated by the same controller, which improves the utilization rate of the control system and reduces the cost; and optical fiber is used for communication between the controller and the stepless arc extinguishing coil and the active power compensator, which reduces the probability of interference and improves the reliability of the product.

[0016] In addition, for substations that have installed stepless arc suppression coils, there is no need to replace them with turn-adjustable arc suppression coils. The full compensation part can be directly added to achieve full compensation of the reactive component, active component and harmonic component of the grounding current, saving equipment investment and reducing installation workload and time. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the system wiring diagram of the present invention;

[0018] Figure 2 It is a voltage adjustment flow chart of the present invention.

[0019] Among them: JDB. Grounding transformer, XH. Stepless arc suppression coil, KM. High-voltage switch, B. Step-up transformer, APC. Active power compensator, KZQ. Controller, LC. Adjustment mechanism. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] A full compensation device using a stepless arc extinguishing coil, the structure of which is as follows Figure 1 As shown, it includes a grounding transformer JDB, a stepless regulating arc extinguishing coil XH, an adjusting mechanism LC and a full compensation part. The adjusting mechanism LC is connected to the controlled end of the stepless regulating arc extinguishing coil XH, the grounding transformer JDB is connected to the system bus ABC, the stepless regulating arc extinguishing coil XH is connected in series between the neutral point of the grounding transformer JDB and the ground, and the full compensation part is connected to the controlled end of the stepless regulating arc extinguishing coil XH. It is used to adjust the inductive reactance of the stepless regulating arc extinguishing coil XH when the system is operating normally, and can fully compensate the system when a single-phase grounding fault occurs in the system.

[0022] The full compensation part includes active power compensator APC, controller KZQ, step-up transformer B, and high-voltage switch KM. The high-voltage switch KM and step-up transformer B are connected in series between the neutral point of the grounding transformer JDB and the ground. The active power compensator APC is connected in parallel to the secondary side of the step-up transformer B. The controller KZQ is connected to the high-voltage switch KM, the active power compensator APC, and the controlled end of the regulating mechanism LC respectively. The setting of the high-voltage switch KM can disconnect the active power compensator APC from the line when the active power compensator APC fails, which is convenient for maintenance.

[0023] In the present invention, the stepless regulating arc extinguishing coil XH can be an adjustable inductance arc extinguishing coil controlled by power electronic devices such as an air gap regulating arc extinguishing coil, a phase-controlled arc extinguishing coil, a biasing arc extinguishing coil or a magnetically controlled arc extinguishing coil; the corresponding regulating mechanism can be a moving iron core regulating device, a thyristor regulating device or an excitation device. Of course, the stepless regulating arc extinguishing coil of the present invention can also be used in series or in parallel with a damping resistor.

[0024] To ensure the reliability of data transmission, the controller KZQ of the present invention communicates with the source power compensator APC and the regulating mechanism LC respectively via optical fibers.

[0025] A full compensation method using a stepless arc extinguishing coil is implemented based on the above-mentioned full compensation device. Figure 2 The compensation method proposed by the present invention is described.

[0026] When the system is operating normally, the controller can communicate with the stepless arc extinguishing coil through optical fiber, issue instructions to adjust the inductive reactance of the stepless arc extinguishing coil, calculate the system impedance to ground through the displacement voltage method, and adjust the stepless arc extinguishing coil to the overcompensation state.

[0027] When a single-phase grounding fault occurs in the system, the controller calculates the expected voltage amplitude and phase that the active power compensator APC needs to output according to the system grounding conditions, and adjusts the inductive reactance of the steplessly adjustable arc suppression coil to make it equal to the system's capacitive reactance to ground. Then the controller controls the active power compensator APC through optical fiber to output the amplitude and phase of the voltage across the steplessly adjustable arc suppression coil.

[0028] After the active power compensator APC is connected to the grid, the output voltage amplitude of the active power compensator APC is gradually adjusted according to the calculated voltage difference. During the adjustment process, the output current of the active power compensator APC is detected in real time. When the output current of the active power compensator APC reaches 0.8 times the rated current of the active power compensator APC (settable), the output voltage amplitude of the active power compensator APC is stopped from being adjusted; then the inductive reactance of the steplessly adjustable arc extinguishing coil XH is adjusted through the adjusting mechanism LC to reduce the output current of the active power compensator APC. When the output current of the active power compensator APC is the smallest, it indicates that the system's ground capacitance is completely compensated by the steplessly adjustable arc extinguishing coil inductive current.

[0029] Finally, commands are sent down through the optical fiber to control the active power compensator APC to continue to increase the output voltage amplitude through step-by-step adjustment, and finally reach the expected voltage amplitude of the active power compensator APC.

[0030] After the output voltage amplitude is adjusted, keep the output voltage amplitude unchanged, and then start adjusting the output voltage phase of the active power compensator APC. The phase adjustment process is the same as the amplitude adjustment method. When the output current of the active power compensator APC reaches 0.8 times (settable) of the rated current, stop adjusting the output voltage phase of the active power compensator APC, and then continue to adjust the inductive reactance value of the stepless arc suppression coil to finally reach the expected voltage phase and amplitude of the active power compensator APC, and realize full compensation for the grounding current and fault point voltage.

[0031] When the active power compensator APC output voltage adjustment is disturbed, when the voltage is reduced and then increased again, the above steps are still taken to gradually increase the voltage to the expected value.

Claims

1. A full compensation method using a stepless arc extinguishing coil, characterized in that: The compensation method is implemented based on a full compensation device; The full compensation device comprises a grounding transformer (JDB) connected to the system bus, a stepless regulating arc extinguishing coil (XH) is connected in series between the neutral point of the grounding transformer (JDB) and the ground, and a regulating mechanism (LC) is connected to the controlled end of the stepless regulating arc extinguishing coil (XH); the controlled end of the stepless regulating arc extinguishing coil (XH) is connected to a full compensation part for compensating the system when a single-phase grounding fault occurs in the system, and the full compensation part comprises an active power compensator (APC), a controller (KZQ) and a step-up transformer (B), the step-up transformer (B) is connected between the neutral point of the grounding transformer (JDB) and the ground, the active power compensator (APC) is connected in parallel to the secondary side of the step-up transformer (B), and the controller (KZQ) is respectively connected to the active power compensator (APC) and the controlled end of the regulating mechanism (LC); The specific full compensation method is as follows: when a single-phase grounding occurs in the system, the controller (KZQ) calculates the expected voltage that the active power compensator (APC) needs to output according to the system grounding condition; secondly, the active power compensator (APC) is controlled to be connected to the grid according to the amplitude and phase of the voltage at both ends of the stepless arc extinguishing coil; after the active power compensator (APC) is connected to the grid, the controller (KZQ) adjusts the inductive reactance of the stepless arc extinguishing coil (XH) through the regulating mechanism (LC) until the output current of the active power compensator (APC) is minimum; Then, the active power compensator (APC) is controlled by the optical fiber to adjust the output voltage of the active power compensator (APC) to the expected voltage through step-by-step adjustment according to the issued instructions.

2. A full compensation method using a stepless arc extinguishing coil according to claim 1, characterized in that: The steplessly adjustable arc extinguishing coil (XH) is an air gap adjustable arc extinguishing coil, a phase controlled arc extinguishing coil, a bias magnetic arc extinguishing coil or a magnetically controlled arc extinguishing coil.

3. A full compensation method using a stepless arc extinguishing coil according to claim 1, characterized in that: The controller (KZQ) communicates with the source power compensator (APC) and the regulating mechanism (LC) respectively via optical fibers.

4. A full compensation method using a stepless arc extinguishing coil according to claim 1, characterized in that: A high-voltage switch (KM) is connected in series between the neutral point of the step-up transformer (B) and the grounding transformer (JDB), and a controlled end of the high-voltage switch (KM) is connected to an output end of a controller (KZQ).

5. A full compensation method using a stepless arc extinguishing coil according to claim 1, characterized in that: The adjustment of the output voltage of the active power compensator (APC) includes amplitude adjustment and phase adjustment.

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