Current and voltage transducers provide instrument level signals to protective relays. Protective relay accuracy and performance are directly related to the steady state and transient performance of the instrument transformers. Protective relays are designed to operate in a shorter time than the time period of the transient disturbance during a system fault. Large instrument transformer transie...

Power systems should have acceptable reliability in order to operate properly. Highly available and dependable protective relays help to obtain the desirable reliability. The relays should be periodically evaluated during specific intervals to achieve the mentioned characteristics. The Routine Test Interval (RTI) should be optimized in order to economically maximize the reliability of the prote...

More and more sub-stations are retrofitted with numerical relays, meters and monitoring devices. Most often, the older relay gets replaced with a newer relay with the rest of the installation such as Current Transformer (CT) and lead remaining undisturbed. Utilities have standardized on their older current transformers and want to maintain the same current transformer specifications throughout ...

There are two main approaches to realize a receiver front-end. However, they have drawbacks when fully-integrated on a single chip. One direction to realize this front-end is to use a transformer that can convert the single RF output of the LNA to the differential input of mixer [4]. Another way to do this is to use a narrow-band two stage tuned LNA [5] that can provide a differential output. H...

This paper proposes a method to obtain a protected voltage gain by employing a protection circuit for the voltage doubler or multiplier circuit in an isolated tyde DC-DC Converter. The entire set up consists of a phase shift converter with a protected bridge/voltage doubler rectifier on the output side. The operating frequency of the phase shift converter is 20-25kHz (depending on the requireme...

In order to solve the problems of protection misoperation and refusing operate caused by lack measurement information in smart substation, a substation method which can effectively eliminate influence transformer inrush current bus CT saturation when connecting line is missing proposed. Through theoretical analysis synthesis based on Kirchhoff law, it proved that will lead misjudgment different...

protection systems have vital role in network reliability in short circuit mode and proper operating for relays. current transformer often in transient and saturation under short circuit mode causes mal-operation of relays which will have undesirable effects. therefore, proper and quick identification of current transformer saturation is so important. in this paper, an artificial neural network...

Transformer inrush currents were traditionally evaluated by means of Fourier analysis. Such approach affects the design of transformer differential relays concerning their immunity to inrush currents. This paper presents a statistical tool named maximum entropy method (MEM), which seems to provide a reliable and computationally efficient tool for identification inrush currents on two different ...