There are many reasons for over voltages in power system. The overvoltage causes number of effect in the power system. It may cause insulation failure of the equipments, malfunction of the equipments. Overvoltage can cause damage to components connected to the power supply and lead to insulation failure, damage to electronic components, heating, flashovers, etc. Over voltages occur in a system ...

500kV substation is especially important to the grid of our country, once it encounters lightning damage, the safety and reliability of the whole power system will be directly affected. As lightning intruding waves will cause overvoltage on electric equipments by intruding from the transmission line or straightly stroking the substation, which seriously influences the insulation level of equipm...

In recent years, with the rapid development of offshore wind turbines (WTs), the problem of lightning strikes has become more and more prominent. In order to reduce the failure rate caused by the transient overvoltage of lightning struck offshore WTs, the influencing factors and the response rules of transient overvoltage are analyzed. In this paper, a new integrated electromagnetic transient m...

Piezoelectric traveling wave rotary ultrasonic motors are motors that generate torque by using the friction force between a piezoelectric composite ring (or disk-shaped stator) and a metallic ring (or disk-shaped rotor) when a traveling wave is excited in the stator. The motor speed is proportional to the amplitude of the traveling wave and, in order to obtain large amplitudes, the stator is ex...

The challenge of designing robust electronic circuitry often results in a design with a multitude of discrete protection components with associated cost, design time, and space additions. This article discusses fault protected switch architecture, along with the performance benefits and other advantages it offers vs. traditional discrete protection solutions. A new novel switch architecture and...

The continuous operation of 1000 MW large hydro generators in China is great value to the implementation “double carbon strategy” and power grid safety. However, with increase single unit capacity generator, problems fault grounding current neutral point voltage drift become more prominent, traditional analysis methods cannot accurately obtain dynamic data. Therefore, starting from mode taking ...

This paper elaborates on several important outstanding issues in the state-of-art of overvoltage protection selection for modern wind farms. The lack of experience with this still-new technology, together with the inherent complexity of wind farm electrical systems, entails several unresolved issues pertinent to the topic of overvoltage protection, particularly in relation to lightning-initiate...

As non-controllable power sources, photovoltaics (PV) can create overvoltage in low voltage (LV) distribution feeders during periods of high generation and low load. This is usually prevented passively by limiting the penetration level of PV to very conservative values, even if the critical periods rarely occur. Alternatively, one can use active power curtailment (APC) techniques, reducing the ...

This paper studies the effect of new suggested ferroresonance limiter on controlling ferroresonance oscillations in the power transformer. It is expected that this limiter generally can control the ferroresonance. For studying these phenomena, at first ferroresonance is introduced and a general modeling approach is given. A simple case of ferroresonance in a three phase transformer is used to i...