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Power System Transient Study

lightning strike in the evening
The electrical power system is highly nonlinear and dynamic by its nature. The state of the system is changing continuously due to load demand response, circuit breaker operation, fault, and atmospheric disturbances such as lightning. In such events, the system is forced to transition to a new state. During this transition, the energy stored in the power system and its components will be redistributed in a very short time and thus, the electrical equipment will be exposed to fundamentally different voltages and frequencies, resulting in higher stress in the equipment. This added stress may lead to equipment failure and poses an increased risk to system reliability.

Electromagnetic Transient (EMT) Study is a computer-based analysis and simulation tool used to determine voltage, current, frequency, and torque during the transient state of a power system. The transient phenomenon is classified by CIGRE based on the frequency range, as shown in the following table:


Frequency range




0.1 Hz - 3 kHz

Low frequency oscillation

Temporary over voltage


60 Hz – 20 kHz

Slow front Surge

Switching over voltage


10 KHz - 3 MHz

Fast front Surge

Lightning over voltage


100 KHz – 50 MHz

Very fast front surge

GIS restrike over voltage

Our EMT studies are supported by state-of-the-art Real Time Digital Simulator (RTDS) and high voltage labs for any testing and investigation, if required. The following studies are conducted in compliance with IEC or IEEE standards:

  1. Comprehensive Insulation Coordination Study
  2. Temporary and switching over voltage study
  3. Transient Recovery Voltage study (TRV)
  4. Power System Resonance study
  5. Sub Synchronous Resonance study (SSR)
  6. Harmonic study
  7. Capacitor bank switching study