48-pulse STATCOM Using High Impedance Capable TSB and SSN

In this model, a 100-Mvar STATCOM regulates voltage on a three-bus 500-kV system. The 48-pulse STATCOM uses a Voltage-Sourced Converter (VSC) made of four 12-pulse three-level GTO inverters. The four sets of three-phase voltages obtained at the output of the four three-level inverters are applied to the secondary windings of four phase-shifting transformers (+/-7.5 deg. phase shifts). The fundamental components of voltages obtained on the 500 kV sides of the transformers are added in phase by the serial connection of primary windings.

During steady-state operation, the STATCOM control system keeps the fundamental component of the VSC voltage in phase with the system voltage. If the voltage generated by the VSC is higher (or lower) than the system voltage, the STATCOM generates (or absorbs) reactive power. The amount of reactive power depends on the VSC voltage magnitude and on the transformer leakage reactance.

The model uses high-impedance capable Time-Stamped Bridges (TSB or interpolating switching-function-based inverter) to simulate the STATCOM. Notably, the TSB supports rectifying mode and high-impedance mode that can occur when GTO pulses are blocked. In the model Console, the user can block the GTO pulses of the STATCOM.

This is an updated ADGRID-01 model with High-Impedance TSB and SSN. SSN is not mandatory in the present form of the model but it would be more useful when modeling a more complex grid.

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References

C. Dufour, J. Mahseredjian, J. Bélanger, "A Combined State-Space Nodal Method for the Simulation of Power System Transients", IEEE Transactions on Power Delivery, Vol. 26, no. 2, April 2011 (ISSN 0885-8977), pp. 928-935