The difference between 110KV and 220KV grid relay protection

1. The difference between 110kV and 220kV power grid relay protection

KV is generally only equipped with three-stage interphase distance and grounding distance protection and three-stage zero sequence protection, plus three-phase reclosing (110KV switch is generally three-phase linkage) reclosing has the function of detecting no voltage and detecting the same period, and some add an asymmetric fault sequential quick action protection.

KV is generally equipped with high-frequency protection (high-frequency distance and high-frequency zero sequence) and three-stage interphase distance and grounding distance protection and three-stage zero sequence protection (sometimes with four sections) and three-phase comprehensive reclosing (reclosing mode can be single-weight, triple and comprehensive weight) 220KV protection to be double-oriented, that is, there are two sets of completely independent protection, any one set has the above functions, 220kV switch is generally operated in phase, so it is also equipped with failure protection. **Luxin generally has a set of overcurrent protection when the new power is transmitted, and it is not invested during normal operation.

2. Study the abnormal working conditions of power system failures and endangering safe operation, and take anti-accident automation measures to countermeasures. Because in the process of its development, relays with contacts were mainly used to protect the power system and its components (generators, transformers, transmission lines, busbars, etc.) from damage, so it is referred to as relay protection.

The protection of 10kV distribution network lines is mainly as follows: quick-break protection, delayed quick-break protection, time-limited overcurrent protection, anti-time overcurrent protection, low-voltage protection, overvoltage protection, Jiandansun cave control PT disconnection, reclosing. In addition, it is also necessary to consider the installation environment such as temperature, electromagnetic interference, communication mode, whether to network, RS-485, Ethernet, communication protocol must be public, whether there is the possibility of networking, etc.

Main protection, distance, zero sequence, recloser, this is the protection of 220kV line; There is also three-phase inconsistent protection for 220kV circuit breaker;

Among them, the main protection can be divided into high-frequency channel and Fibre Channel according to the channel;

The operating principle of the main protection is as follows: high-frequency distance, high-frequency direction (the direction of the load is started), optical fiber differential (the current difference between the two sides), longitudinal distance, etc.

Grounding, quick break, overcurrent, undervoltage, over.

The distribution network line is generally the two main configurations of overcurrent protection and quick-break protection, with other protection and self-safety devices such as overload and reclosing!

The main protections are:

Quick break, overcurrent, overload, differential, high backup and low backup, oil temperature ultra-high temperature, heavy gas, and some are equipped with grounding protection (zero sequence protection).

1. Main protection for short-circuit faults

The main protection of transformer short-circuit fault mainly includes longitudinal protection, heavy gas protection and pressure release protection. In addition, according to the capacity, voltage level and structural characteristics of the transformer, it can be equipped with zero differential protection and sub-side differential protection.

2. Backup protection for short-circuit faults

At present, there are more types of short-circuit fault backup protection used on power transformers, including: composite voltage lock-up overcurrent protection; Zero-sequence over-current or zero-sequence direction over-current protection; Negative sequence overcurrent or negative sequence direction overcurrent protection; Composite voltage latching power direction protection; low-impedance protection, etc.

3. Abnormal operation protection:

The abnormal operation protection of transformer mainly includes: overload protection, overexcitation protection, transformer neutral point gap protection, light gas protection, temperature, oil level protection and cooler total stop protection.

The transformer protection of 110 includes: gas relay protection, coil thermometer, oil top thermometer, high-voltage CT protection, pressure release protection, oil level protection, etc.

"Differential (transverse, longitudinal) protection, overcurrent protection, overvoltage protection, gas protection, temperature (oil temperature, coil temperature) protection, grounding protection, pressure relief valve (this is not relay protection), etc"

The second floor is very complete. Oil level protection (early warning), there may also be zero sequence current protection for large grounding systems.

There were four ways to classify them: we were teaching them by the fourth

According to the classification of protected objects, there are transmission line protection and main equipment protection (such as generator, transformer, busbar, reactor, capacitor and other protection).

According to the protection function, there are short-circuit fault protection and abnormal operation protection. The former can be divided into primary protection, backup protection and auxiliary protection; The latter can be divided into overload protection, loss of magnetism protection, loss of step protection, low-frequency protection, non-full-phase operation protection, etc.

According to the semaphore of the protection device for comparison and calculation processing, there are analog protection and digital protection. All electromechanical, rectifier, transistor and integrated circuit (operational amplifier) protection devices, which directly reflect the continuous analog quantity of the input signal, are analog protection; The protection device of microprocessor and microcomputer is adopted, which reflects the discrete digital quantity after sampling and modular-to-digital conversion of analog quantity, which is digital protection.

According to the principle of protection action, it is classified as overcurrent protection, low voltage protection, overvoltage protection, power direction protection, distance protection, differential protection, high frequency (carrier) protection, etc.

Hope it helps!