The selection of relay protection devices and what is the role of relay protection devices

The relay is an automatic switching element with isolation function, which is widely used in remote control, telemetry, communication, automatic control, mechatronics and power electronic equipment, and is one of the most important control components.

..Relays generally have an induction mechanism (input part) that can reflect certain input variables (such as current, voltage, power, impedance, frequency, temperature, pressure, speed, light, etc.); There is an actuator (output part) that can realize "on" and "off" control of the controlled circuit; Between the input and output parts of the relay, there is also an intermediate mechanism (drive part) that couples and isolates the input quantity, processes the function, and drives the output part.

..As a control element, in summary, the relay has the following functions:

..1) Expand the scope of control. For example, when the control signal of a multi-contact relay reaches a certain value, it can be changed, interrupted, and connected to multiple circuits at the same time according to the different forms of contact groups.

..2) Zoom in. For example, sensitive relays, intermediate relays, etc., can control a very large power circuit with a very small amount of control.

..3) Composite signals. For example, when a plurality of control signals are input into a multi-winding relay in a specified form, a predetermined control effect is achieved after comparative synthesis.

..4) Automatic, remote control, monitoring. For example, relays on automatics, together with other electrical appliances, can form a programmed control circuit to achieve automatic operation.

The factory specializes in the production of all kinds of time relays, electromagnetic relays, electronic relays, high-power relays, liquid level relays, solid-state relays, high-power relays, small relays, timers, counter relays, etc.

Control and protection are its main roles.

Relay protection device often refers to the device that changes one or more protection elements and logic elements to be assembled together according to requirements and completes a specific protection function in the power system.

Types of commonly used relay protection devices:

1. Current protection;

2. Voltage protection;

3. Gas protection;

4. Differential protection;

5. High-frequency protection;

6. Distance protection;

7. Balance protection of the flat bush;

8. Negative sequence and zero sequence protection;

9. Direction protection.

Relay protection device often refers to one or more protection elements and logic elements are combined together according to the requirements and complete a special protection function in the power excavation system.

Types of commonly used relay protection devices:

1. Current protection;

2. Voltage protection;

3. Gas protection;

4. Differential protection is peerless;

5. High-frequency protection;

6. Distance protection;

7. Balance protection;

8. Negative sequence and zero sequence protection;

9. Direction protection.