CN210925803U - Monitoring circuit of disconnecting switch opening circuit based on the principle of voltage monitoring - Google Patents

Abstract

The utility model relates to an isolation switch opening circuit monitoring circuit based on the principle of voltage monitoring. Its characteristics are: including the positive pole of the DC power supply, the positive pole of the DC power supply sequentially passes through the normally open contact of the closing contactor, the normally closed contact of the opening contactor, the first normally closed auxiliary contact, the coil of the closing contactor, and the motor. The loop switch and the stop button are connected to the negative pole of the DC power supply, and the positive pole of the DC power supply also passes through the normally open contact of the opening contactor, the normally closed contact of the closing contactor, the second normally open auxiliary contact, and the open contact of the opening contactor. The coil is then connected to the midpoint of the series connection between the coil of the aforementioned closing contactor and the motor circuit switch. The utility model not only solves the hidden danger that the existing converter station cannot monitor the opening circuit of the high-voltage side isolation switch of the DC filter, but also does not need to consider the problem of matching the resistance values of the monitoring relay and the opening and closing coil of the circuit breaker monitoring circuit, ensuring that There is no risk of misoperation of the protection.

Description

Monitoring circuit of disconnecting switch opening circuit based on the principle of voltage monitoring

technical field

The utility model relates to an isolation switch opening circuit monitoring circuit based on the principle of voltage monitoring.

Background technique

In conventional DC and UHV DC transmission systems, different numbers of DC filters are configured on the DC side, which are usually connected as parallel filters between the DC pole busbar and the neutral line (or ground) of the converter station for Eliminate even-order characteristic harmonics generated by the DC side system. The DC filter is in a state of being put into operation under normal conditions, and its high-voltage side isolation switch is in a closed state. One of the consequences of the action of the DC filter protection is to trip the isolation switch on the high-voltage side. If the opening circuit of the isolation switch is disconnected at this time, it will cause serious consequences of the filter protection refusal to operate, and endanger the safe and stable operation of the equipment power grid.

Therefore, it is very necessary to realize the monitoring of the disconnecting switch circuit under normal operation. In the monitoring method of the traditional AC system, only the monitoring of the circuit breaker opening circuit does not involve the monitoring of the isolation switch and the control circuit of the grounding switch. The monitoring of the circuit breaker opening circuit is realized by the voltage dividing effect of the large resistance relay, but this method is difficult to realize in the isolation switch, and the improper selection of the relay can easily cause the protection to malfunction.

Utility model content

The purpose of the utility model is to provide a circuit for monitoring the opening circuit of the isolation switch based on the principle of voltage monitoring, which can eliminate the hidden danger that the existing converter station cannot monitor the opening circuit of the isolation switch on the high-voltage side of the DC filter, thereby avoiding the protection refusal to operate happened.

A monitoring circuit of disconnecting switch opening circuit based on the principle of voltage monitoring, which is special in that it includes a positive pole of a DC power supply, and the positive pole of the DC power supply sequentially passes through the normally open contact of the closing contactor and the normally closed contact of the opening contactor. point, the first normally closed auxiliary contact, the coil of the closing contactor, the motor circuit switch, and the stop button are connected to the negative pole of the DC power supply, and the positive pole of the DC power supply also passes through the normally open contact of the opening contactor and the The normally closed contact, the second normally open auxiliary contact, and the coil of the opening contactor are then connected with the coil of the closing contactor and the midpoint of the series connection of the motor circuit switch; it also includes a far and near control handle, and the three The input terminals are respectively connected to the positive pole of the DC power supply, and the remote closing terminal of the three output terminals of the remote and near control handle is connected to the series midpoint of the normally open contact of the closing contactor and the normally closed contact of the opening contactor. , the remote opening end of the three output ends of the far and near control handle is connected with the series midpoint of the normally open contact of the aforementioned opening contactor and the normally closed contact of the closing contactor, and the three outputs of the far and near control handle The local terminal in the terminal is connected with the aforementioned remote closing terminal through the closing button, and the local terminal is also connected with the aforementioned remote switching terminal through the opening button; it also includes a voltage monitoring module, and the positive terminal of the voltage monitoring module is wired. The terminal is grounded, the negative terminal of the voltage monitoring module is connected to the aforementioned remote opening terminal, and the alarm terminal of the voltage monitoring module is connected to the substation monitoring system.

The utility model provides an isolation switch opening circuit monitoring circuit based on the principle of voltage monitoring. It has been proved by trial that it not only solves the hidden danger that the existing converter station cannot monitor the isolation switch opening circuit of the high voltage side of the DC filter, but also avoids protection In the event of refusal to act, it is not necessary to consider the problem of matching the resistance values of the circuit breaker monitoring circuit monitoring relay and the opening and closing coil to ensure that the risk of protection misoperation will not be caused.

Description of drawings

Accompanying drawing 1 is the electrical principle diagram of the utility model.

Detailed ways

The utility model provides an isolation switch opening circuit monitoring circuit based on the principle of voltage monitoring. , The first normally closed auxiliary contact, the coil of the closing contactor, the motor circuit switch, and the stop button are connected to the negative pole of the DC power supply, and the positive pole of the DC power supply also passes through the normally open contact of the opening contactor and the normally closed contactor The closing contact, the second normally open auxiliary contact, and the coil of the opening contactor are connected to the middle point of the series connection between the coil of the closing contactor and the motor circuit switch;

It also includes a far and near control handle, the three input ends of the far and near control handle are respectively connected with the positive pole of the DC power supply, and the remote closing end of the three output ends of the far and near control handle is connected to the aforementioned closing contactor. The series midpoint connection of the normally closed contacts of the gate contactor, the remote opening end of the three output ends of the remote and near control handle is connected with the series connection of the normally open contacts of the opening contactor and the normally closed contacts of the closing contactor. The mid-point connection, the local end of the three output ends of the far and near control handle is connected with the aforementioned remote closing end through the closing button, and the local end is also connected with the aforementioned remote opening end through the opening button;

It also includes a voltage monitoring module, the positive terminal of the voltage monitoring module is grounded, the negative terminal of the voltage monitoring module is connected to the aforementioned remote switching terminal, and the alarm terminal of the voltage monitoring module is connected to the substation monitoring system.

The voltage monitoring module adopts the existing conventional voltage monitor.

The use method and working principle of the present utility model are:

The K1 relay circuit is the closing circuit, the K2 relay circuit is the opening circuit, the inner contact of the dotted line in front of the S6 remote control handle is the opening command issued by the protection, and S1 and S2 are the auxiliary contacts of the isolation switch. Without the opening circuit monitoring function, if the disconnector is in the closed state, the disconnection occurs at the contacts K2 to K1 of the opening circuit, which will cause the opening circuit to be disconnected, and the issued opening command will not be able to complete the isolation. The opening action of the switch will cause the protection to refuse to act at this time, causing serious consequences.

After adding the opening circuit monitoring function, it is assumed that the control power supply is 110V DC at this time, and the "low voltage" alarm setting value of the voltage monitoring module is 40V. We can get that the voltage to ground at the "negative" terminal connection is "-55V", so the voltage measured by the voltage monitoring module is "+55V". When the gate circuit K2 to K1 is disconnected, the voltage to ground at the "negative" terminal connection is "0V", and the voltage measured by the voltage monitoring module is "0V", reaching the "low voltage" alarm. value, the voltage monitoring relay "voltage low" alarm contact is closed. The monitoring system receives an alarm indicating that the abnormality of the disconnecting switch opening circuit needs to be dealt with in time, which effectively avoids the hidden danger of protection refusal caused by the abnormality of the opening circuit.

Claims (1)

1. A monitoring circuit of a separating brake loop of an isolating switch based on a voltage monitoring principle is characterized in that: the direct-current power supply system comprises a direct-current power supply anode, wherein the direct-current power supply anode is connected with a direct-current power supply cathode sequentially through a normally open contact of a closing contactor, a normally closed contact of an opening contactor, a first normally closed auxiliary contact, a coil of the closing contactor, a motor loop switch and a stop button, and is connected with a normally open contact of the opening contactor, a normally closed contact of the closing contactor, a second normally open auxiliary contact and a coil of the opening contactor and then connected with a series midpoint of the coil of the closing contactor and the motor loop switch;

the remote and near control device further comprises a remote and near control handle, three input ends of the remote and near control handle are respectively connected with the positive pole of a direct-current power supply, a remote switching-on end of three output ends of the remote and near control handle is connected with the series midpoint of the normally open contact of the switching-on contactor and the normally closed contact of the switching-off contactor, a remote switching-off end of the three output ends of the remote and near control handle is connected with the series midpoint of the normally open contact of the switching-off contactor and the normally closed contact of the switching-on contactor, the local end of the three output ends of the remote and near control handle is connected with the remote switching-on end through a switching-on button, and the local end of the three output ends of the remote and near control handle is also;

the monitoring system also comprises a voltage monitoring module, wherein a positive terminal of the voltage monitoring module is grounded, a negative terminal of the voltage monitoring module is connected with the remote brake-separating end, and an alarm end of the voltage monitoring module is connected with a substation monitoring system.

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