# Power System Analysis

Power system analysis covers short-circuit studies, load flow studies, arc flash studies etc. Articles here cover some of the basics too which are important if you want to understand some of these studies. The basics include per unit systems, symmetrical components, current ratings etc.

## Transient Recovery Voltage and Its Effect on a Circuit Breaker

One problem that is pervasive in the power grid and not well understood is called the Transient Recovery Voltage (TRV). When a short-circuit due to a fault in high voltage or medium voltage system is switched-out by a circuit breaker, the voltage across the breaker poles rapidly increases; as high as twice the operating voltage. …

## Who Controls the Power Grid in USA?

Have you wondered what goes on behind the scenes of electric power delivery in America? This post explains who is controlling the flow of power on the grid and who is policing to ensure the reliability requirements are met.

## Per Unit System: Problem Solved For Easy Understanding (continued)

In this post, we calculate the full load current drawn by the load. See linked post to view how the per unit impedances were calculated.

## Choosing Between Resistor and Reactor for Neutral Ground Impedance

Faults involving ground produce high fault current magnitude especially when the transformer(s) neutral is solidly grounded. The neutral ground circuit in the transformer provides the return path for the fault currents. To limit this current, impedance โ either in the form of a reactor or a resistor โ is installed in the neutral circuit. See …

## Power Cable Neutral and System Grounding

Installing medium voltage power cables underground comes with its own set of challenges. From the engineering standpoint, there are several factors one needs to consider before installing the cable. The most overlooked if not well understood factor is the type of power cable that’s required for the application and when to ground the cable’s neutral …