Capacitor closing inrush current treatment device based on fast circuit breaker
By combining fast circuit breakers and spark gaps with current-limiting components, precise control of capacitor closing inrush current is achieved, solving the problem of poor control effect of existing devices, protecting equipment and improving power quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ANHUI SENSITIVE POWER EQUIP CO LTD
- Filing Date
- 2025-04-07
- Publication Date
- 2026-04-17
AI Technical Summary
Existing capacitor inrush current control devices are ineffective, leading to damage to circuit breaker and capacitor structures, increasing the probability of re-breakdown, and affecting service life.
By employing fast circuit breakers and spark gaps in conjunction with current limiting components, and monitoring grid signals through voltage and current transformers, the on/off state of the circuit breakers and spark gaps is controlled. In conjunction with the current limiting component RL, inrush current is limited, thereby achieving precise control.
It effectively limits the inrush current to within 1.8 times the rated current, protecting circuit breakers and capacitors, and improving service life and power quality.
Smart Images
Figure CN224138728U_ABST
Abstract
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 closing of a fast circuit breaker capacitor. Background Technology
[0002] To improve the power factor and power quality of the power grid, existing distribution networks are connected to reactive power compensation devices. Among them, capacitors have become one of the most widely used reactive power compensation devices in the power system due to their advantages such as low cost, ease of installation and maintenance.
[0003] The transient phenomenon during the reactive power compensation process of capacitors can lead to inrush current. Inrush current occurs when the capacitors used for reactive power compensation are in an uncharged state. At the moment of closing, the current flowing through the capacitor is limited only by its circuit impedance. Since the circuit impedance is extremely small at this time, the resulting inrush current will theoretically be very large. When the inrush current is severe, it will damage the circuit breaker structure used to connect the parallel capacitors, thereby increasing the probability of the circuit breaker experiencing a re-breakdown during interruption. It will also damage the insulation components of the capacitor bank, affecting its service life.
[0004] Most existing capacitor closing inrush current control devices limit the closing inrush current through RL impedance. However, because the instantaneous current of the closing inrush current is very large, it can still reach 5-10 times the rated current even after relying solely on RL limitation, which affects the service life.
[0005] To address this issue, we propose a device for controlling inrush current during capacitor closing based on fast circuit breakers. Utility Model Content
[0006] The purpose of this invention is to solve the problem of poor treatment effect in the existing technology, and to propose a device for controlling inrush current when closing capacitors of fast circuit breakers.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] A device for controlling inrush current during capacitor closing based on a fast circuit breaker includes a capacitor, a circuit breaker assembly, a voltage transformer, 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 capacitor. The current transformer is connected in series at the outgoing terminal of the transformer, and the high-voltage terminal of the voltage transformer is connected in parallel at the incoming terminal of the circuit breaker assembly.
[0009] The circuit breaking assembly includes a controller and a circuit breaking unit. The circuit breaking assembly controls the opening and closing of the circuit breaking unit by coordinating the data from the current transformer and the voltage transformer with the controller.
[0010] The circuit breaking unit includes a circuit breaker K1, a current limiting component RL, and a spark gap GAP connected in series. The input terminal of the circuit breaker K1 is connected to the external network, and the output terminal of the spark gap GAP is connected to a capacitor. A circuit breaker K2 is connected in parallel between the input terminal of the circuit breaker K1 and the output terminal of the spark gap GAP. The controller controls the on / off state of the circuit breaker K1, the circuit breaker K2, and the spark gap GAP by means of programmable logic device instructions.
[0011] Preferably, the circuit breaking component includes a measurement module, a programmable logic device, a controller, and a circuit breaking unit connected in sequence. The measurement module is connected to a current transformer and a voltage transformer, respectively. The programmable logic device processes the measurement module data, and the controller controls the circuit breaking unit to open or close based on the instructions of the programmable logic device.
[0012] Preferably, the current limiting component RL includes a resistor and an inductor connected in series.
[0013] Preferably, both circuit breaker K1 and circuit breaker K2 are fast circuit breakers.
[0014] Preferably, the secondary side of the voltage transformer is grounded.
[0015] Preferably, the spark gap (GAP) input terminal is connected to the current limiting component (RL) output terminal, the spark gap (GAP) output terminal is connected to the capacitor, and the spark gap control terminal is connected to the controller.
[0016] In summary, the technical effects and advantages of this utility model are as follows: This inrush current control device based on fast circuit breaker capacitor closing achieves real-time monitoring of the power grid voltage signal through a voltage transformer and a measurement module, realizes phase switching through a spark gap (GAP), limits the inrush current through a current limiting component (RL), and achieves short-circuiting after current stabilization through a circuit breaker (K2). Compared with existing devices, it avoids the problem of poor inrush current limiting effect by RL alone, and improves the inrush current control effect. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the structure of this utility model;
[0018] Figure 2 This is a block diagram of the circuit breaker unit structure in this utility model. Detailed Implementation
[0019] 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.
[0020] Reference Figure 1A device for controlling inrush current during capacitor closing based on a fast circuit breaker includes a capacitor, a circuit breaker assembly, a voltage transformer, 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 capacitor. The current transformer is connected in series at the outgoing terminal of the transformer, and the high-voltage terminal of the voltage transformer is connected in parallel at the incoming terminal of the circuit breaker assembly.
[0021] The circuit breaking assembly includes a controller and a circuit breaking unit. The circuit breaking assembly controls the opening and closing of the circuit breaking unit by coordinating the data from the current transformer and voltage transformer with the controller.
[0022] The circuit breaking unit includes a circuit breaker K1, a current limiting component RL, and a spark gap GAP connected in series. The incoming terminal of the circuit breaker K1 is connected to the external network, and the outgoing terminal of the spark gap GAP is connected to a capacitor. A circuit breaker K2 is connected in parallel between the incoming terminal of the circuit breaker K1 and the outgoing terminal of the spark gap GAP. The controller controls the opening and closing of the circuit breaker K1, the circuit breaker K2, and the spark gap GAP by means of programmable logic device instructions.
[0023] This inrush current control device based on fast circuit breaker capacitor closing first measures the voltage signal on the external grid side using a voltage transformer and a measurement module. When closing is required, the controller first drives the circuit breaker K1 to close, and then the programmable logic device detects the voltage signal until the grid voltage waveform reaches a zero-crossing point. At this point, the controller controls the spark gap GAP to connect, and with the current limiting component RL, the inrush current is limited to approximately 1.8 times the rated current. Once the measurement module detects that the current transformer value is stable, the controller drives the circuit breaker K2 to close, completing the capacitor closing operation.
[0024] The circuit breaker assembly includes a measurement module, a programmable logic device (PLD), a controller, and a circuit breaker unit connected in sequence. The measurement module is connected to a current transformer and a voltage transformer, respectively. The PLD processes the data from the measurement module, and the controller controls the circuit breaker unit's on / off state based on instructions from the PLD. The measurement module, PLD, and controller are all existing technologies and will not be described in detail.
[0025] The current limiting component RL includes a resistor and an inductor connected in series to assist in limiting and managing inrush current, avoiding excessive inrush current caused by phase separation error.
[0026] Both circuit breakers K1 and K2 are fast circuit breakers. Since the switching response time of ordinary circuit breakers is too long, the effect is not good, and it will also prolong the conduction time of the spark gap GAP. Therefore, fast circuit breakers with a response time of only a few milliseconds should be selected.
[0027] The secondary side of the voltage transformer is grounded, which, in conjunction with the measurement module, enables the measurement of the grid voltage.
[0028] The incoming terminal of the spark gap (GAP) is connected to the outgoing terminal of the current limiting component (RL), the outgoing terminal of the spark gap (GAP) is connected to the capacitor, and the control terminal of the spark gap is connected to the controller. Because the spark gap (GAP) has an extremely short conduction response time, it can conduct more accurately at the zero-crossing point compared to a circuit breaker, thus improving the inrush current control effect.
[0029] 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 inrush current management based on fast breaker capacitor switching, comprising a capacitor, a breaker assembly, a voltage transformer 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 capacitor, the current transformer is connected in series at the outgoing terminal of the transformer, and the high-voltage terminal of the voltage transformer is connected in parallel at the incoming terminal of the circuit breaker assembly. The circuit breaking assembly includes a controller and a circuit breaking unit. The circuit breaking assembly controls the opening and closing of the circuit breaking unit by coordinating the data from the current transformer and the voltage transformer with the controller. The circuit breaking unit includes a circuit breaker K1, a current limiting component RL, and a spark gap GAP connected in series. The input terminal of the circuit breaker K1 is connected to the external network, and the output terminal of the spark gap GAP is connected to a capacitor. A circuit breaker K2 is connected in parallel between the input terminal of the circuit breaker K1 and the output terminal of the spark gap GAP. The controller controls the on / off state of the circuit breaker K1, the circuit breaker K2, and the spark gap GAP by means of programmable logic device instructions.
2. A device for inrush current mitigation based on the capacitor switching-in of a fast circuit breaker according to claim 1, characterized in that, The circuit breaking assembly includes a measurement module, a programmable logic device, a controller, and a circuit breaking unit connected in sequence. The measurement module is connected to a current transformer and a voltage transformer, respectively. The programmable logic device processes the measurement module data, and the controller controls the circuit breaking unit to open and close based on the instructions of the programmable logic device.
3. The device for surge current control based on the capacitor closing of the fast circuit breaker according to claim 1, characterized in that, The current limiting component RL includes a resistor and an inductor connected in series.
4. The device for surge current control based on the capacitor closing of the fast circuit breaker according to claim 1, characterized in that, Both circuit breakers K1 and K2 are fast circuit breakers.
5. The device for surge current management based on the capacitor closing of the fast circuit breaker according to claim 2, characterized in that, The secondary side of the voltage transformer is grounded.
6. A device for surge current management based on the capacitor closing of a fast circuit breaker according to claim 1, characterized in that, The spark gap (GAP) input terminal is connected to the current limiting component (RL) output terminal, the spark gap (GAP) output terminal is connected to the capacitor, and the spark gap control terminal is connected to the controller.