What are the main functions of relay protection devices?

In the event of a fault or abnormal operation, the relay protection device will act quickly to realize fault isolation and issue an alarm to ensure the safety of the power system.

When the power components in the power system (such as generators, lines, etc.) or the power system itself fail and endanger the safe operation of the power system, it can send a warning signal to the operation duty personnel in time, or directly send a trip command to the controlled circuit breaker to terminate the development of these automatic measures and equipment. The complete set of equipment that realizes this kind of automation measure is generally referred to as relay protection device.

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The relay protection device can respond to the fault and abnormal working state of the electrical equipment, and automatically act quickly and selectively on the circuit breaker to remove the faulty equipment from the system, ensure that the non-faulty equipment continues to operate normally, limit the accident to a minimum, improve the reliability of the system operation, and ensure the safe and continuous power supply to the user to the greatest extent.

Protective relay devices are generally measured by. It consists of three basic parts: logic and execution. The function of the measurement part is to measure the physical quantities of the protected equipment, such as electric current.

Voltage. Impedance. The phase difference between voltage and current, etc., is then compared with a given setting value to determine whether the electromechanical system is faulty or abnormal, and then the corresponding signal is output to the logic element.

Relay protection device is also called relay protection calibrator, the main function is to automatically cut off the power supply when electrical equipment and electrical lines fail, avoid the expansion of accidents, and ensure the safety of the power grid and people, therefore, the role of relay protection device must have selectivity, rapidity, sensitivity and reliability.

1. Selectivity, when the system fails, the protection device should have a selective part of the fault. The non-faulty part continues to work.

2. When there is a short circuit, fast troubleshooting can reduce the scope of the fault. Reduce the damage caused by short-circuit current, reduce the impact on the user, and improve the stability of the system.

3. Sensitivity refers to the sensitivity of the relay protection device to the possible failure and normal operation of the protection device. The sensitivity of the protective device is expressed by the sensitivity coefficient kl.

The sensitivity coefficients of the protective devices that reflect the increase in the number of parameters in the case of a fault are as follows:

The sensitivity coefficient of the protection device reflecting the reduction of the parameters at the time of the fault is.

4. Reliability, relay protection device at any time to maintain a complete and flexible working state, in the event of a failure, the protection device should act in a timely and reliable manner, should not have its own defects, to prevent failure, for this reason, the construction is required to be urgent, simple and accurate, the construction is correct, the debugging is correct, and the operation and maintenance are proper.

Respondent: Huatian Power.

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 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.

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.