Capacitor harmonic resonance overvoltage detection method and protection device

Abstract

The invention discloses a capacitor harmonic resonance overvoltage detection method and protection device. The capacitor harmonic resonance overvoltage detection method and protection device adopt advanced hardware equipment, are combined with a harmonic resonance analysis algorithm, and reliably protect a capacitor. The protection device mainly comprises a master control circuit board, a harmonic collection and conditioning circuit, a voltage following circuit, a multi-path conversion switch circuit, an AD conversion module, an FPGA control module, a 485 communication circuit, a 232 communication circuit, and a man-machine interaction module circuit board. The capacitor harmonic resonance overvoltage detection method mainly comprises the steps of analog acquisition and analog acquisition control and transmission with an algorithm module, an algorithm module and power grid remote control communication module, an algorithm module and man-machine interaction module, and a database module. The capacitor harmonic resonance overvoltage detection method and protection device have the advantages of being capable of detecting harmonic voltage in real time, reasonable in structural design, high in practicability, low in cost and high in work efficiency.

Description

Technical field [0001] The invention relates to the technical field of power system harmonics, in particular to a capacitor harmonic resonance overvoltage detection method and protection device. Background technique [0002] In recent years, with the rapid development of power electronic technology, the application of power electronic equipment in the power industry has become increasingly popular. At the same time, a large number of arc equipment and many other non-linear loads have also been put into use, and these equipment have caused distortions in the voltage and current waveforms in the system. Distortion causes a large number of harmonics to be generated, causing more and more harmonic pollution. [0003] One of the main hazards of harmonic generation is harmonic resonance. In order to compensate for reactive power and improve power factor, power companies have increased the use of capacitor banks. The introduced capacitors and the capacitors and inductive components in the...

AI Technical Summary

Problems solved by technology

[0002] In recent years, with the rapid development of power electronic technology, the application of power electronic equipment in the power industry has become more and more popular. At the same time, a large number of arc equipment and many other nonlinear loads have also been put into use, and these equipment distort the voltage and current waveforms in the system Distortion, resulting in a large number of harmonics, causing more and more harmonic pollution

[0003] One of the main harms caused by harmonics is harmonic resonance. In order to compensate reactive power and improve power factor, power companies have increased the use of capacitor banks in large quantities. The introduced capacitors, capacitors and inductive components in the system may cause local resonance. The voltage in turn damages the capacitor

The parallel resonance of the power system will cause overvoltage, and the series resonance will cause overcurrent, resulting in local overheating of the system, amplifying the local current and voltage of the capacitor, accelerating the insulation aging of electrical equipment, and causing damage to related electrical equipment

When the system contains harmonics close to the resonance frequency, the harmonics will be amplified several times to dozens of times, so that the capacitor bank will be burned due to overvoltage

[0004] At present, a lot of work is mainly focused on the development of harmonic suppression devices, such as passive filters, active filters, etc., while ignoring the protection of the capacitor bank inside the system, resulting in damage to a large number of capacitors due to harmonics, affecting reactive power compensation devices normal work, and the design of the power factor of the reactive power compensation device reduces the working efficiency

However, the existing capacitor overvoltage protection device cannot detect the capacitor harmonic voltage in real time. Chinese patent CN02105002.3 discloses a power resonance protection module. The main technical solution is that one of the circuits has the functions of analysis, interpretation and counting. Calculate the effective value of the voltage on the capacitor after voltage division; the circuit uses the fundamental and non-fundamental components of the voltage to calculate the effective value of the overall current of the capacitor; Cut off the system or change the impedance characteristics to protect

This patent requires a power resonance protection module for each capacitor in the system, which is suitable for simple power systems, but it will take time and effort for complex power systems, and the protection device is only for the capacitor voltage under a single harmonic, without consideration Capacitor voltage at total harmonics

Images