A device for governing inrush current based on quick breaker transformer closing

Abstract

The utility model discloses a kind of based on quick circuit breaker transformer closing rush current management device, belong to closing rush current management technical field, including transformer, circuit breaking component, voltage transformer A, voltage transformer B and current transformer, the circuit breaking component incoming line end is connected with outer net, the circuit breaking component outgoing line end is connected with the incoming line end of transformer.This based on quick circuit breaker transformer closing rush current management device, by voltage transformer B, current transformer cooperation measurement module, the voltage and current signal of load end are measured, cooperate programmable logic device, the residual magnetism of transformer is calculated, cooperate controller, the on-off of circuit breaking unit is realized, compared with existing device, avoid the influence of residual magnetism when secondary closing, so that the problem that the voltage and the magnetic field of core are no longer completely synchronous, improve the management effect to rush current.

Description

Technical Field

[0001] This utility model belongs to the field of inrush current control technology, and in particular relates to a device for controlling inrush current during the closing of a transformer based on a fast circuit breaker. Background Technology

[0002] When a transformer is closed under no-load or light-load conditions, a large inrush current will be generated, which can be 6 to 8 times the rated current, and in severe cases, it can be more than ten times. The inrush current has the following hazards to the power grid: (1) it causes relay protection to malfunction; (2) it deteriorates the power quality; (3) it causes damage to transformers and circuit breakers due to excessive electrodynamic force; (4) the DC component in the inrush current causes the magnetic circuit of the current transformer to be over-magnetized, thereby greatly reducing the measurement accuracy and the correct operation rate of the relay protection device.

[0003] Existing methods for controlling inrush current during transformer operation mostly employ phase-by-phase closing strategies. While these strategies can limit inrush current during the initial closing, residual magnetism remains on the transformer core after the transformer is de-energized. Subsequent closing of the transformer is affected by this residual magnetism, causing the voltage and the core's magnetic field to become out of sync, thus impacting the effectiveness of inrush current control.

[0004] To address this issue, we propose a device for controlling inrush current during transformer closing based on a fast circuit breaker. Utility Model Content

[0005] The purpose of this invention is to solve the problem of inrush current control caused by residual magnetism in transformers in the prior art, and to propose an inrush current control device based on a fast circuit breaker transformer.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A device for controlling inrush current during transformer closing based on a fast circuit breaker includes a transformer, a circuit breaker assembly, voltage transformer A, voltage transformer B, and a current transformer. The incoming terminal of the circuit breaker assembly is connected to the external power grid, and the outgoing terminal of the circuit breaker assembly is connected to the incoming terminal of the transformer. The high-voltage terminal of voltage transformer A is connected in parallel to the incoming terminal of the circuit breaker assembly, the high-voltage terminal of voltage transformer B is connected in parallel to the outgoing terminal of the transformer, and the current transformer is connected in series at the outgoing terminal of the transformer.

[0008] The circuit breaking assembly includes a measurement module, a programmable logic device, a controller, and a circuit breaking unit that are electrically connected in sequence. The measurement module is electrically connected to voltage transformer A, voltage transformer B, and current transformer respectively. The programmable logic device processes the data from the measurement module and drives the controller to control the on / off state of the circuit breaking unit. The input terminal of the circuit breaking unit is connected to the external network, and the output terminal of the circuit breaking unit is connected to the input terminal of the transformer.

[0009] Preferably, the circuit breaking unit includes circuit breaker K1, circuit breaker K2, and spark gap GAP. Circuit breaker K1 and spark gap GAP are connected in series between the external power grid and the transformer. Circuit breaker K2 is connected in parallel on both sides of circuit breaker K1 and spark gap GAP. The controller drives and controls the on / off switching of circuit breaker K1, circuit breaker K2, and spark gap GAP.

[0010] Preferably, both circuit breaker K1 and circuit breaker K2 are fast circuit breakers.

[0011] Preferably, the incoming terminal of the circuit breaker K1 is connected to the external network, the outgoing terminal of the circuit breaker K1 is connected to the incoming terminal of the spark gap GAP, the outgoing terminal of the spark gap GAP is connected to the incoming terminal of the transformer, and the control terminal of the spark gap GAP is connected to the controller.

[0012] Preferably, the secondary sides of both voltage transformer A and voltage transformer B are grounded.

[0013] In summary, the technical effects and advantages of this utility model are as follows: Compared with existing devices, this inrush current control device based on fast circuit breaker transformers, through voltage transformer B and current transformer in conjunction with a measurement module, measures the voltage and current signals at the load end, calculates the residual magnetism of the transformer in conjunction with a programmable logic device, and realizes the switching of the circuit breaker unit in conjunction with a controller. Compared with existing devices, it avoids the problem of voltage and core magnetic field not being completely synchronized due to the influence of residual magnetism during secondary closing, thus improving the inrush current control effect. Attached Figure Description

[0014] Figure 1 This is a structural block diagram of the present utility model;

[0015] Figure 2 This is a block diagram of the circuit breaker unit structure in this utility model. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0017] Reference Figure 1-2 A device for controlling inrush current during transformer closing based on a fast circuit breaker includes a transformer, a circuit breaker assembly, voltage transformer A, voltage transformer B, and current transformers. The incoming terminal of the circuit breaker assembly is connected to the external power grid, and the outgoing terminal of the circuit breaker assembly is connected to the incoming terminal of the transformer. The high-voltage terminal of voltage transformer A is connected in parallel to the incoming terminal of the circuit breaker assembly, and the high-voltage terminal of voltage transformer B is connected in parallel to the outgoing terminal of the transformer. The current transformers are connected in series at the outgoing terminal of the transformer. The side of the transformer facing voltage transformer A can be referred to as the external power grid side, and the other side as the load side.

[0018] The circuit breaker assembly includes a measurement module, a programmable logic device, a controller, and a circuit breaker unit, which are connected in sequence. The measurement module is electrically connected to voltage transformer A, voltage transformer B, and current transformer, respectively. The programmable logic device processes the data from the measurement module and drives the controller to control the on / off state of the circuit breaker unit. The input terminal of the circuit breaker unit is connected to the external power grid, and the output terminal of the circuit breaker unit is connected to the input terminal of the transformer.

[0019] This inrush current control device based on a fast circuit breaker transformer first measures the voltage signal on the external grid side using a voltage transformer A and a measurement module. When closing is required, a programmable logic device detects the voltage signal until the grid voltage waveform reaches a zero-crossing point, at which point the drive controller controls the circuit breaker unit to close. When disconnection is required, the drive controller controls the circuit breaker unit to disconnect when the grid voltage waveform reaches a zero-crossing point.

[0020] After a circuit breaker trips, residual magnetism remains in the transformer core. At this time, voltage and current signals on the load side are measured using voltage transformer B and a current transformer in conjunction with a measurement module. The residual magnetism of the transformer is then calculated using programmable logic devices. When the circuit breaker is closed again, the timing of the closing is delayed compared to the zero-crossing point, ensuring that the closing occurs when the grid voltage and the residual magnetism of the core are relatively aligned, thereby reducing inrush current. The delay is typically between 1 and 5 ms.

[0021] The circuit breaker unit includes circuit breaker K1, circuit breaker K2, and spark gap GAP. Circuit breaker K1 and spark gap GAP are connected in series between the external power grid and the transformer. Circuit breaker K2 is connected in parallel on both sides of circuit breaker K1 and spark gap GAP. The controller drives and controls the opening and closing of circuit breaker K1, circuit breaker K2, and spark gap GAP.

[0022] In this circuit breaker unit, during closing, the controller first drives circuit breaker K1 to close. At this time, when the power grid waveform reaches the appropriate angle, the controller drives the spark gap GAP to conduct, thereby achieving precise closing. After the spark gap GAP conducts, the controller then drives circuit breaker K2 to close, thereby short-circuiting the spark gap GAP and preventing it from burning out due to prolonged conduction.

[0023] Both circuit breakers K1 and K2 are fast circuit breakers. Since the triggering time needs to be the zero-crossing point of the grid voltage waveform, i.e., the closing is triggered at the zero-crossing moment, the switching response time of ordinary circuit breakers is too long, resulting in poor performance and also prolonging the conduction time of the spark gap (GAP). Therefore, a fast circuit breaker with a response time of only a few milliseconds should be selected.

[0024] The incoming terminal of circuit breaker K1 is connected to the external power grid, the outgoing terminal of circuit breaker K1 is connected to the incoming terminal of spark gap GAP, the outgoing terminal of spark gap GAP is connected to the incoming terminal of transformer, and the control terminal of spark gap GAP is connected to the controller. The controller drives spark gap GAP to conduct. Due to the extremely short conduction response time of spark gap GAP, it can conduct more accurately at the zero-crossing point compared to circuit breaker, thus improving the inrush current control effect.

[0025] The secondary sides of voltage transformers A and B are both grounded, which, together with the measurement module, enables voltage measurement on the external grid side and the load side.

[0026] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A device for controlling inrush current during transformer closing based on a fast circuit breaker, comprising a transformer, a circuit breaker assembly, voltage transformer A, voltage transformer B, and a current transformer, characterized in that, The incoming terminal of the circuit breaker assembly is connected to the external network, the outgoing terminal of the circuit breaker assembly is connected to the incoming terminal of the transformer, the high-voltage terminal of the voltage transformer A is connected in parallel to the incoming terminal of the circuit breaker assembly, the high-voltage terminal of the voltage transformer B is connected in parallel to the outgoing terminal of the transformer, and the current transformers are connected in series at the outgoing terminal of the transformer. The circuit breaking assembly includes a measurement module, a programmable logic device, a controller, and a circuit breaking unit that are electrically connected in sequence. The measurement module is electrically connected to voltage transformer A, voltage transformer B, and current transformer respectively. The programmable logic device processes the data from the measurement module and drives the controller to control the on / off state of the circuit breaking unit. The input terminal of the circuit breaking unit is connected to the external network, and the output terminal of the circuit breaking unit is connected to the input terminal of the transformer.

2. The inrush current control device based on a fast circuit breaker transformer according to claim 1, characterized in that, The circuit breaking unit includes circuit breaker K1, circuit breaker K2, and spark gap GAP. Circuit breaker K1 and spark gap GAP are connected in series between the external power grid and the transformer. Circuit breaker K2 is connected in parallel on both sides of circuit breaker K1 and spark gap GAP. The controller drives and controls the on / off of circuit breaker K1, circuit breaker K2, and spark gap GAP.

3. The inrush current control device based on a fast circuit breaker transformer according to claim 2, characterized in that, Both circuit breakers K1 and K2 are fast circuit breakers.

4. The inrush current control device based on a fast circuit breaker transformer according to claim 3, characterized in that, The circuit breaker K1 input terminal is connected to the external network, the circuit breaker K1 output terminal is connected to the spark gap GAP input terminal, the spark gap GAP output terminal is connected to the transformer input terminal, and the spark gap GAP control terminal is connected to the controller.

5. The inrush current control device based on a fast circuit breaker transformer according to claim 1, characterized in that, The secondary sides of both voltage transformer A and voltage transformer B are grounded.

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