A circuit to prevent a 6kV vacuum contactor switch from accidentally closing automatically.

Abstract

This utility model discloses a circuit for preventing a 6kV vacuum contactor switch from erroneously closing automatically, relating to the field of safety protection technology for high-voltage electrical control equipment. It includes a main control circuit and a suppression circuit, both electrically connected to a control power supply and connected in parallel. The main control circuit includes an inductor L1 and a time relay KT1, both electrically connected to the control power supply and connected in parallel, and both connected in parallel with the suppression circuit. This utility model uses auxiliary contacts CH1 / CH3 to monitor the voltage status in real time, achieving millisecond-level rapid disconnection. Simultaneously, the time relay KT1 ensures complete release of electromagnetic energy, and capacitors C1 / C2 specifically absorb the energy coupled from the cable's distributed capacitance and inductance, thus constructing a triple protection system of electrical detection, timing control, and energy absorption.

Description

Technical Field

[0001] This utility model relates to the field of safety protection technology for high-voltage electrical control equipment, specifically a circuit for preventing a 6kV vacuum contactor switch from accidentally closing automatically. Background Technology

[0002] In 6kV power distribution systems in power plants, chemical plants, metallurgical plants, and other industrial sectors, vacuum contactor switches (VSC switches) are critical electrical control devices. According to the 2023 edition of the "Twenty-Five Countermeasures" issued by the State Energy Group, 6kV switches must be equipped with live grounding switches (grounding switches). This interlocking device uses an electromagnet structure, and its working principle is equivalent to an inductor (L). Together with the distributed capacitance to ground (C) formed by the long-distance control cable and the line resistance (R), it constitutes an R-LC circuit.

[0003] However, at the instant the control power is disconnected, according to the inductance characteristic formula, the sudden change in current in the electromagnet will induce a high voltage across its terminals. Simultaneously, according to the capacitance characteristic formula, the distributed capacitance of a long cable (typically exceeding 50 meters) will couple with the inductance energy, generating a transient superimposed voltage as high as 225V. This voltage will directly act on the closing coil, causing the switch to automatically close erroneously without any operational command. Furthermore, if the switch is in the operating position, it will cause loads such as motors to start erroneously, posing a risk of personal injury to on-site maintenance personnel (e.g., in belt conveyor or fan operation scenarios), and may even lead to a major equipment accident. Utility Model Content

[0004] The purpose of this invention is to provide a circuit to prevent a 6kV vacuum contactor switch from automatically closing erroneously, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a circuit for preventing a 6kV vacuum contactor switch from automatically closing erroneously, comprising a main control circuit and a suppression circuit, wherein the main control circuit and the suppression circuit are electrically connected to a control power supply, and the main control circuit and the suppression circuit are connected in parallel with each other;

[0006] The main control circuit includes an inductor L1 and a time relay KT1. Both the inductor L1 and the time relay KT1 are electrically connected to the control power supply. At the same time, the inductor L1 and the time relay KT1 are connected in parallel with each other, and both are connected in parallel with the suppression circuit.

[0007] Furthermore, the time relay KT1 is electrically connected to the closing coil YC, and the series circuit formed by the closing coil YC and the time relay KT1 is connected in parallel with the suppression circuit and the inductor L1.

[0008] Furthermore, the suppression circuit includes a switch S and a contactor KT. One end of the switch S is electrically connected to the positive terminal of the control power supply, and the other end of the switch S is electrically connected to the negative terminal of the control power supply through the contactor KT. At the same time, one end of the switch S is electrically connected to capacitor C1, and the other end is electrically connected to capacitor C2.

[0009] Furthermore, both capacitors C1 and C2 are electrically connected to the CH3 auxiliary contact of the time relay KT1.

[0010] Furthermore, the CH1 auxiliary contact of the time relay KT1 is electrically connected to the positive terminal of the control power supply, and the CH7 auxiliary contact of the time relay KT1 is electrically connected to the negative terminal of the control power supply.

[0011] Furthermore, the switch S is configured as a mechanical or electronic interlocking switch.

[0012] Furthermore, the delay setting value of the time relay KT1 is greater than the discharge time.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] Firstly, this utility model, through the parallel design of the main control circuit and the suppression circuit, enables the CH1 / CH3 auxiliary contacts to monitor the voltage status in real time and achieve millisecond-level rapid disconnection. At the same time, through the time relay KT1, it ensures that the electromagnetic energy is completely released, and through the capacitors C1 / C2, it specifically absorbs the energy coupled by the distributed capacitance and inductance of the cable, thereby constructing a triple protection of electrical detection, timing control and energy absorption.

[0015] Secondly, this utility model can match cable lengths of 50-300 meters by adjusting the delay parameter of the time relay KT1. At the same time, the capacitance values ​​of capacitors C1 / C2 can be flexibly configured according to the characteristics of the electromagnet on site, thus adapting to various working conditions. Attached Figure Description

[0016] Figure 1 This is the circuit diagram for preventing the 6kV vacuum contactor switch from accidentally closing automatically. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0018] refer to Figure 1 This embodiment provides a circuit to prevent a 6kV vacuum contactor switch from automatically closing erroneously. The circuit includes a main control circuit and a suppression circuit, both electrically connected to a control power supply, and connected in parallel. It is worth noting that the control power supply voltage in this embodiment is DC 110V or 220V, suitable for the control circuit of a 6kV vacuum contactor.

[0019] In this embodiment, the main control circuit includes an inductor L1 and a time relay KT1. The time relay KT1 is electrically connected to the closing coil YC. The series circuit formed by the closing coil YC and the time relay KT1 is connected in parallel with the suppression circuit and the inductor L1. The series circuit formed by the closing coil YC and the time relay KT1, along with the inductor L1, are all electrically connected to the control power supply. It is worth noting that the delay setting value of the time relay KT1 is greater than the discharge time to ensure that the closing operation is prohibited before the electromagnet's energy is fully released after power failure.

[0020] Furthermore, the suppression circuit includes a switch S and a contactor KT. One end of switch S is electrically connected to the positive terminal of the control power supply, and the other end of switch S is electrically connected to the negative terminal of the control power supply through contactor KT. Simultaneously, one end of switch S is electrically connected to capacitor C1, and the other end is electrically connected to capacitor C2. It is worth noting that switch S is configured as a mechanical or electronic interlocking switch to detect the status of the grounding switch. When the grounding switch is not completely open, switch S remains open, thereby preventing the closing circuit from being connected.

[0021] Furthermore, the CH3 auxiliary contact of time relay KT1 is electrically connected to both capacitors C1 and C2, the CH1 auxiliary contact of time relay KT1 is electrically connected to the positive terminal of the control power supply, and the CH7 auxiliary contact of time relay KT1 is electrically connected to the negative terminal of the control power supply. It is worth noting that capacitors C1 and C2 are both electrolytic capacitors or film capacitors, and their capacitance values ​​can be specifically set according to the cable's distributed capacitance and the electromagnet's inductance. Therefore, they will not be specifically described in this embodiment, in order to effectively absorb transient oscillation energy.

[0022] Specifically, the voltage status of the power supply can be controlled in real time through the auxiliary contacts CH1 and CH3 of the time relay KT1. That is, when the control power supply is energized, the auxiliary contact CH1 of the time relay KT1 will immediately open, completely cutting off the closing circuit. Even if the switch S is misoperated, it will not be able to close. When the control power supply is de-energized, the auxiliary contact CH1 of the time relay KT1 remains closed, which allows it to enter the pre-closing state.

[0023] Furthermore, when the operator closes switch S, the CH3 auxiliary contact of time relay KT1 will perform a secondary voltage verification. If an abnormal voltage is detected, the CH3 auxiliary contact of time relay KT1 will immediately open to complete the closing process. If no abnormal voltage is detected, the CH3 auxiliary contact of time relay KT1 will remain closed, and time relay KT1 will be activated simultaneously.

[0024] Furthermore, when time relay KT1 starts timing, it provides time for electromagnetic energy release, avoiding interference from transient voltages. Simultaneously, when time relay KT1 finishes timing, it closes, energizing contactor KT. At this point, the auxiliary contact CH7 of time relay KT1 closes, connecting the power supply to the closing coil YC, thereby driving the vacuum contactor to complete the closing operation.

[0025] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended embodiments and their equivalents.

Claims

1. A circuit for preventing the false automatic closing of a 6 kV vacuum contactor switch, characterized in that, It includes a main control circuit and a suppression circuit, both of which are electrically connected to a control power supply, and are connected in parallel with each other. The main control circuit includes an inductor L1 and a time relay KT1. Both the inductor L1 and the time relay KT1 are electrically connected to the control power supply. At the same time, the inductor L1 and the time relay KT1 are connected in parallel with each other, and both are connected in parallel with the suppression circuit.

2. The circuit for preventing the false automatic closing of the switch of the 6kV vacuum contactor according to claim 1, characterized in that, The time relay KT1 is electrically connected to the closing coil YC. The series circuit formed by the closing coil YC and the time relay KT1 is connected in parallel with the suppression circuit and the inductor L1.

3. A circuit for preventing erroneous automatic closing of a 6kV vacuum contactor switch according to claim 1 or 2, characterized in that, The suppression circuit includes a switch S and a contactor KT. One end of the switch S is electrically connected to the positive terminal of the control power supply, and the other end of the switch S is electrically connected to the negative terminal of the control power supply through the contactor KT. At the same time, one end of the switch S is electrically connected to capacitor C1, and the other end is electrically connected to capacitor C2.

4. The circuit for preventing erroneous automatic closing of a 6kV vacuum contactor switch according to claim 3, characterized in that, Both capacitors C1 and C2 are electrically connected to the CH3 auxiliary contact of time relay KT1.

5. A circuit for preventing erroneous automatic closing of a 6kV vacuum contactor switch according to claim 1 or 2, characterized in that, The CH1 auxiliary contact of the time relay KT1 is electrically connected to the positive terminal of the control power supply, and the CH7 auxiliary contact of the time relay KT1 is electrically connected to the negative terminal of the control power supply.

6. The circuit for preventing erroneous automatic closing of a 6kV vacuum contactor switch according to claim 3, characterized in that, The switch S is configured as a mechanical or electronic interlocking switch.

7. The circuit for preventing erroneous automatic closing of a 6kV vacuum contactor switch according to claim 1, characterized in that, The delay setting value of the time relay KT1 is greater than the discharge time.

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