engleski

Analysis of ferroresonance due to deenergization of inductive voltage transformer

Ferroresonance is a non-linear resonance phenomenon that can affect power networks. Power networks are made up of a large number of saturable inductances (power transformers, inductive voltage transformers (IVT), shunt reactors), as well as capacitors (cables, long lines, capacitor voltage transformers, series or shunt capacitor banks, voltage grading capacitors in circuit-breakers). They thus present scenarios under which ferroresonance can occur. The abnormal rates of harmonics and transient or steady state overvoltages and overcurrents that it causes are often dangerous for electrical equipment. Therefore, power system must function beyond the boundary of ferroresonant regions, and the occurrence of such response when planning of network expansion takes place should be minimized. In order to achieve this, a comprehensive understanding of such phenomenon is essential for power system engineers, that is by looking into the variations of system parameters and transformer parameters which are known to directly influence ferroresonance response so as to gain a better understanding about its behavior. Because of its non-linear characteristic, inductive voltage transformer has a possibility of causing ferroresonance with capacitances present in the network. A situation with circuit breaker disconnecting, after which the voltage transformer remains energized through the circuit breaker grading capacitance was analyzed in EMTP-RV simulations. Various ferroresonant modes were analyzed by carrying out the sensitivity studies of both the system and the transformer parameters.

inductive voltage transformer; ferroresonance; sensitivity analysis; EMTP-RV

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