CN111610436A - A monitoring circuit for closing micro switch of medium voltage contactor in nuclear power plant - Google Patents

Abstract

A monitoring circuit for a medium-voltage contactor closing microswitch in a nuclear power plant is characterized in that it includes a contactor closing power module, a comprehensive monitoring relay, an opening and closing auxiliary switch, a closing circuit microswitch, and a position monitoring microswitch. The upper end of the contactor closing power supply module and the position monitoring microswitch are connected to the positive terminal of the control electric power, while the lower end of the position monitoring microswitch is connected with the comprehensive monitoring relay to form a series circuit. The contactor closing power supply module, The lower end of the comprehensive monitoring relay is connected to the upper end of the closing circuit microswitch, the lower end of the closing circuit microswitch is connected to the negative control terminal, and the two ends of the opening and closing auxiliary switch are respectively connected to the two ends of the closing circuit microswitch. The terminals form a parallel circuit.

Description

A monitoring circuit for closing micro switch of medium voltage contactor in nuclear power plant

technical field

The technology belongs to the field of electrical switch control loop monitoring, and specifically relates to a design scheme for monitoring the state of a microswitch in a switch closing circuit of a medium-voltage contactor switch of a safety-related load in a nuclear power plant.

Background technique

核电厂普遍的中压应急配电系统接触器开关设计中，未设计合闸回路监测功能，一般在开关柜柜体和接触器手车上各设计一组微动开关，位于柜体的一组用于手车工作位置时闭合接通状态监测，位于接触器手车的一组用于在工作位时闭合接通合闸回路，但两组微动开关因为结构和安装的差异性，存在位置监测微动开关已闭合但合闸回路微动开关未闭合的情况。经国内核电运行发现，存在以下几个问题：

In the contactor switch design of the medium-voltage emergency power distribution system common in nuclear power plants, the closing circuit monitoring function is not designed. Generally, a group of microswitches are designed on the switchgear cabinet and the contactor handcart. It is used to monitor the closing and closing state of the handcart in the working position. One group of the contactor handcart is used to close the closing circuit when it is in the working position, but the two groups of microswitches have different positions due to the difference in structure and installation. Monitors the condition that the microswitch is closed but the closing circuit microswitch is not closed. After domestic nuclear power operation, it is found that there are the following problems:

开关柜接触器手车摇入工作位操作未完全到位无法发现，位置监测微动开关已动作导致操作者认为操作到位，但合闸回路微动开关未闭合，合闸回路不导通，导致接触器接收合闸信号时无法闭合，安全相关设施无法可靠启动；

The switch cabinet contactor handcart is not fully in place and cannot be found. The position monitoring micro switch has acted, so that the operator thinks that the operation is in place, but the micro switch of the closing circuit is not closed, and the closing circuit is not conducting, resulting in contact When the device receives the closing signal, it cannot be closed, and the safety-related facilities cannot be reliably started;

接触器合闸回路微动开关故障无法及时发现处理，导致接触器接收合闸信号时无法闭合，安全相关设施无法可靠启动；

The failure of the micro-switch of the contactor closing circuit cannot be detected and handled in time, resulting in the failure of the contactor to close when receiving the closing signal, and the safety-related facilities cannot be reliably started;

In order to solve this problem, Fujian Fuqing Nuclear Power Co., Ltd. designed a set of closing circuit monitoring scheme through analysis and demonstration and combined with the medium-voltage contactor used on site.

Before implementing this monitoring plan, Fujian Fuqing Nuclear Power Co., Ltd. indirectly judged the closing status of the closing circuit micro switch by measuring the closing circuit voltage to ground. Manual measurement results in a waste of manpower, and the closing circuit may be grounded due to measurement errors or tool defects, resulting in a ground fault in the DC system of the nuclear island of the nuclear power plant.

SUMMARY OF THE INVENTION

The purpose of the present invention is to design a visual monitoring circuit for the hot standby state of the switch, so as to avoid the problem that the hot standby switch cannot be reliably closed due to the inaction of the microswitch in the closing circuit of the switch.

The technical scheme of the present invention is as follows: a monitoring circuit for a medium-voltage contactor closing microswitch in a nuclear power plant, characterized in that it includes a contactor closing power supply module, a comprehensive monitoring relay, an opening and closing auxiliary switch, and a closing circuit microswitch. The upper end of the contactor closing power supply module and the position monitoring micro switch are connected to the control electric positive terminal, and the lower end of the position monitoring micro switch is connected to the comprehensive monitoring relay to form a series circuit. The lower ends of the contactor closing power supply module and the comprehensive monitoring relay are connected to the upper end of the closing circuit microswitch, the lower end of the closing circuit microswitch is connected to the negative control terminal, and the two ends of the opening and closing auxiliary switch are respectively connected to the closing circuit. Both ends of the gate circuit microswitch form a parallel circuit.

The control electric positive terminal is +55V.

The control electric negative terminal is -55V.

The two ends of the opening and closing auxiliary switch are respectively connected to the two ends of the closing circuit micro-switch to form a parallel circuit.

The control electric positive electric terminal is +50V.

The control electric negative terminal is -50V.

The control electric positive electric terminal is +45V.

The control electric negative terminal is -40V.

The control electric positive terminal is +60V.

The control electric positive terminal is -60V.

The significant effect of the present invention is that the switch state monitoring of the closing circuit of the medium-voltage contactor related to the safety of the nuclear power plant is realized, and the problem that the hot standby switch cannot be closed reliably because the operation is not in place or the fault of the micro switch is unknown is solved. , the verification effect is good.

Description of drawings

Figure 1 is a schematic diagram of the medium voltage contactor closing and comprehensive monitoring circuit circuit without closing circuit monitoring;

Fig. 2 is the circuit schematic diagram of the medium-voltage contactor closing and comprehensive monitoring circuit with increased closing micro-switch monitoring according to the present invention;

In the figure: contactor closing power module 1, comprehensive monitoring relay 2, opening and closing auxiliary switch 3, closing circuit microswitch 4, position monitoring microswitch 5

Detailed ways

A monitoring circuit for a medium-voltage contactor closing microswitch in a nuclear power plant, comprising a contactor closing power module 1, a comprehensive monitoring relay 2, an opening and closing auxiliary switch 3, a closing circuit microswitch 4, and a position monitoring microswitch Switch 5, as shown in Figure 2, in which the upper ends of the contactor closing power module 1 and the position monitoring micro switch 5 are connected to the positive control terminal, and the lower end of the position monitoring micro switch 5 is connected to the comprehensive monitoring relay 2. A series circuit is formed. The lower ends of the contactor closing power supply module 1 and the comprehensive monitoring relay 2 are connected to the upper end of the closing circuit microswitch 4, and the lower end of the closing circuit microswitch 4 is connected to the negative control terminal, and the opening and closing Two ends of the auxiliary switch 3 are respectively connected to two ends of the closing circuit micro switch 4 to form a parallel circuit.

A method for monitoring a circuit of a medium-voltage contactor closing microswitch in a nuclear power plant, comprising the following steps:

S1: The medium voltage contactor is moved from the isolation position of the switch cabinet to the working position, and the closing circuit microswitch and the position monitoring microswitch are closed and turned on;

S2: The medium voltage contactor control circuit is powered, and the comprehensive monitoring relay is powered normally.

If the micro switch of the closing circuit is not turned on because the medium voltage contactor is not in place due to the shaking to the working position, or the micro switch of the closing circuit fails to be turned on, the comprehensive monitoring relay cannot be energized, and a monitoring alarm signal will be issued.

Claims (10)

1. The utility model provides a monitoring circuit of micro-gap switch that closes a floodgate of voltage contactor in nuclear power plant which characterized in that: including contactor combined floodgate power module (1), comprehensive monitoring relay (2), divide-shut brake auxiliary switch (3), combined floodgate return circuit micro-gap switch (4), position monitoring micro-gap switch (5), wherein contactor combined floodgate power module (1), the upper end of position monitoring micro-gap switch (5) all connects the positive electric end of control electricity, and the lower extreme of position monitoring micro-gap switch (5) is connected with comprehensive monitoring relay (2) and is constituteed series circuit, contactor combined floodgate power module (1), the upper end of combined floodgate return circuit micro-gap switch (4) is all connected to the lower extreme of comprehensive monitoring relay (2), the lower extreme of combined floodgate return circuit micro-gap switch (4) connects the negative electric end of control electricity.

2. The monitoring circuit of the closing microswitch of the medium voltage contactor in the nuclear power plant as claimed in claim 1, characterized in that: the positive end of the control circuit is + 55V.

3. The monitoring circuit of the closing microswitch of the medium voltage contactor in the nuclear power plant as claimed in claim 1, characterized in that: the negative end of the control electrode is-55V.

4. The monitoring circuit of the closing microswitch of the medium voltage contactor in the nuclear power plant as claimed in claim 1, characterized in that: two ends of the opening and closing auxiliary switch (3) are respectively connected with two ends of the closing loop microswitch (4) to form a parallel circuit.

5. The monitoring circuit of the closing microswitch of the medium voltage contactor in the nuclear power plant as claimed in claim 1, characterized in that: the positive end of the control electrode is + 50V.

6. The monitoring circuit of the closing microswitch of the medium voltage contactor in the nuclear power plant as claimed in claim 1, characterized in that: the negative electricity end of the control electricity is-50V.

7. The monitoring circuit of the closing microswitch of the medium voltage contactor in the nuclear power plant as claimed in claim 1, characterized in that: the positive end of the control electrode is + 45V.

8. The monitoring circuit of the closing microswitch of the medium voltage contactor in the nuclear power plant as claimed in claim 1, characterized in that: the negative end of the control electrode is-40V.

9. The monitoring circuit of the closing microswitch of the medium voltage contactor in the nuclear power plant as claimed in claim 1, characterized in that: the positive end of the control electrode is + 60V.

10. The monitoring circuit of the closing microswitch of the medium voltage contactor in the nuclear power plant as claimed in claim 1, characterized in that: the positive end of the control circuit is-60V.

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