Protection element and current-limiting resonance eliminator

By connecting a current-sensitive resistor and a zinc oxide varistor in series between the neutral point and ground of the voltage transformer, the thermal collapse problem caused by low resistance in the SiC harmonic suppressor during a fault is solved, thus realizing the protection and status monitoring of the voltage transformer.

CN224083188UActive Publication Date: 2026-04-03GUANGXI POWER GRID CORP
0 Cites 2 Cited by

Patent Information

Application Number
CN202520565270.0
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2025-03-28
Publication Date
2026-04-03
Estimated Expiration
2035-03-28

AI Technical Summary

Technical Problem

Existing nonlinear resistor SiC harmonic suppressors have high resistance under normal conditions and low resistance during faults, which cannot effectively suppress the zero-sequence loop current of voltage transformers and may even lead to thermal collapse.

Method used

A protection module consisting of a current-sensitive resistor and a zinc oxide varistor connected in parallel is connected in series between the neutral point of the voltage transformer and ground. The current-sensitive resistor rapidly increases the resistance during a fault, while the zinc oxide varistor conducts under high voltage, thus protecting the current-limiting harmonic suppressor and the voltage transformer.

Benefits of technology

It does not affect system parameters during normal operation, quickly absorbs resonant energy in case of fault, suppresses excitation current below 200mA, protects voltage transformer from saturation and prevents fuses from blowing, and monitors operating status in real time through built-in current sensor.

✦ Generated by Eureka AI based on patent content.
Patent Text Reader

Abstract

The utility model relates to the field of resonance eliminators, and discloses a protection element and a current limiting type resonance eliminator, the protection element comprises at least two groups of protection units, the two adjacent groups of protection units are connected in series, and each protection unit comprises a protection module; the current-limiting resonance eliminator based on the current-sensitive resistor made of the current-sensitive material is connected in series between the PT neutral point and the ground. Under the normal operation condition, the current-limiting resonance eliminator is in a low-resistance state, and system parameters and PT performance are not affected; when excitation energy is generated due to a system fault, the current-limiting resonance eliminator suddenly changes into a high resistance state, quickly absorbs resonance energy, destroys resonance parameters, suppresses PT excitation current below 200mA, and ensures that a voltage transformer is unsaturated and a PT fuse is not fused; and a built-in current sensor is connected, so that the running state of the current-limiting resonance eliminator can be monitored in real time.
Need to check novelty before this filing date? Find Prior Art