Purpose

An annual substation equipment failure report says 3/7 capacitive voltage transformer (CVT) got damaged because of ferroresonance overvoltage. The conventional mitigation circuit fails to protect the transformer as the overvoltage may fall in the range between 2 and 4 per unit. It is necessary to develop a device to suppress the overvoltage as well as overcurrent of the CVT. This study aims to propose the suitability of memristor emulator as a mitigation circuit for ferroresonance.

Design/methodology/approach

The literature implies that a nonlinear circuit can protect the transformer against ferroresonance. An attempt is made with a memristor emulator using Operational Amplifier (OPAMP) for the mitigation of ferroresonance in a prototype transformer. The circuit is simulated using PSpice and validated for its ideal characteristics using hardware implementation. The nonlinear memductance is designed which is required to mitigate the ferroresonance. The mitigation performance has been compared with conventional method along with fast Fourier transform (FFT) analysis.

Findings

While the linear resistor recovers the secondary voltage by 74.1%, the memristor emulator does it by 82.05% during ferroresonance. Also, the total harmonic distortion (THD) of ferroresonance signal found to be 22.06% got improved as 2.56% using memristor emulator.

Research limitations/implications

The suitability of memristor emulator as a mitigation circuit for ferroresonance is proposed in this paper. As ferroresonance occurs in instrument transformers which have extra high voltage (EHV) rated primary windings and (110 V/[110 V/1.732]) rated secondary windings, the mitigation device is proposed to be connected as a nonlinear load across the secondary windings of the transformer. This paper discusses the preliminary work of ferroresonance mitigation in a prototype transformer. The mitigation circuit may have memristor or meminductor for ferroresonance mitigation when they are commercially available in future.

Practical implications

The electronic component-based memristor emulator may not work at 110 V practically as they may be rated at low power. Hence, chemical component-based memristor emulator was developed to do the same. The authors like to clarify that the memristor will be a solution for ferroresonance in future not the memristor emulator circuit.

Social implications

With the real form of memristor, the transistor world will be replaced by it and may have a revolution in the field of electronics, VLSI, etc. This contribution attempts to project the use of memristor in a smaller scale in high-voltage engineering.

Originality/value

The electronic component-based memristor emulator is proposed as a mitigation circuit for ferroresonance. The hypothesis has been verified successfully in a prototype transformer. Testing circuit of memristor emulator involves transformer, practically. The mitigation performance has been compared with conventional method technically and justified with FFT analysis.

中文翻译：

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忆阻器仿真器–用于减少单相变压器中铁磁谐振的非线性负载

目的

年度变电站设备故障报告称3/7电容式电压互感器（CVT）由于铁磁谐振过电压而损坏。传统的缓解电路无法保护变压器，因为过电压可能会落在每单位2至4之间的范围内。有必要开发一种抑制CVT的过电压和过电流的器件。这项研究的目的是提出忆阻器仿真器作为缓解铁磁谐振的电路的适用性。

设计/方法/方法

文献暗示非线性电路可以保护变压器不受铁磁谐振的影响。尝试使用运放（OPAMP）的忆阻器仿真器来减轻原型变压器中的铁磁谐振。该电路使用PSpice进行了仿真，并使用硬件实现对其理想特性进行了验证。设计了非线性磁导，以减轻铁磁谐振。缓解性能已与传统方法以及快速傅立叶变换（FFT）分析进行了比较。

发现

当线性电阻器将二次电压恢复74.1％时，忆阻器仿真器在铁磁谐振期间将二次电压恢复82.05％。另外，使用忆阻器仿真器，发现铁磁谐振信号的总谐波失真（THD）为22.06％，改进为2.56％。

研究局限/意义

本文提出了忆阻器仿真器作为铁磁谐振缓解电路的适用性。由于铁磁谐振发生在具有超高压（EHV）额定初级绕组和（110 V / [110 V / 1.732]）额定次级绕组的互感器中，因此建议将缓解装置作为非线性负载连接到变压器。本文讨论了原型变压器中减轻铁磁谐振的初步工作。当将来在市场上可以买到时，该缓解电路可以具有忆阻器或忆阻器，用于减轻铁磁谐振。

实际影响

基于电子组件的忆阻器仿真器实际上可能无法在110 V下工作，因为它们的额定功率可能较低。因此，开发了基于化学成分的忆阻器仿真器来实现相同的目的。作者想澄清的是，忆阻器将来将是铁磁谐振的解决方案，而不是忆阻器仿真器电路。

社会影响

有了忆阻器的真实形式，晶体管世界将被它取代，并可能在电子，VLSI等领域发生一场革命。这种贡献试图在更高电压的工程中扩大忆阻器的应用范围。

创意/价值

提出了基于电子组件的忆阻器仿真器，作为铁磁谐振的缓解电路。该假设已在原型变压器中得到成功验证。忆阻器仿真器的测试电路实际上涉及变压器。缓解性能已在技术上与常规方法进行了比较，并通过FFT分析得到了证明。