Control loop

It consists of a transmission mechanism and an execution (or operation) mechanism that controls the switch and the controlled object (such as a circuit breaker or disconnector).

Its function is to perform "open" and "close" operations on primary equipment to meet the requirements of changing the system operation mode and fault handling.

For example, the VS1 circuit breaker opening and closing control circuit of the switch cabinet.

Control loop classification

1. According to the degree of automation: manual control and automatic control;
2. According to the control distance: local control and remote control;
3. According to the control method: decentralized control and centralized control;
4. According to the nature of the operating power supply: DC control and AC control;
5. According to the operating power supply voltage and current: high current control and low current control.

Strong current control uses higher voltage (110V, 220V) and larger current (AC 5A), while weak current control uses lower voltage (DC below 60V) and smaller current (AC 0.5-1A).

Signal loop

It consists of a signal sending mechanism, a transmission mechanism and a signal relay.

Its function is to accurately and timely reflect the working status of the corresponding primary and secondary equipment, and provide a reliable basis for operation, adjustment and fault handling for operation and maintenance personnel.

For example, switch cabinet signal lights indicate circuits.

Signal circuit classification

1. According to the nature of the signal: accident signal, warning signal, command signal and position signal;
2. According to the signal display mode: light signal and sound signal;
3. According to the signal reset method, it is divided into manual reset and automatic reset.

Measuring circuit

It consists of various measuring instruments and their related circuits.

Its function is to indicate or record the operating parameters of primary equipment and systems so that operators can understand the operating status of the primary system.

It is the main basis for analyzing power quality, calculating economic indicators, and understanding system trends.

Regulation loop

According to the changes in the operating parameters of the primary equipment, the working status of the primary equipment is adjusted online in real time to meet the operating requirements.

Relay protection and automatic device circuit

Automatically judge the operating status of the primary equipment. When the system fails or operates abnormally, it will automatically trip the circuit breaker (cut off the fault) or send out an abnormal operation signal. After the fault or abnormality disappears, the circuit breaker will be quickly put into operation to restore the normal operation of the system.

Operating power system

It is composed of power supply equipment and power supply network. DC and AC power supply system. Its main function is to provide working power and operating power to control, protection, signal and other circuits.