Wide-area voltage control system of flexible AC transmission system devices to prevent voltage collapse

Hydro-Quebec has identified wide-area control system as a key initiative able to significantly increase the voltage stability of its grid. In this context, an innovative project for wide-area and local voltage control of shunt compensators was initiated. Its main objective is to implement a closed-loop control system on Hydro-Quebec's network to optimise the reactive power support from the dynamic shunt compensators. The outcome of this project is the global and local control of compensators' (GLCCs) system which is based on synchrophasor technology and intelligent electronics devices. Applied to each shunt compensator of Hydro-Quebec's network, this robust voltage control system measures voltage variations in the load area and adjusts the operation set point of each shunt compensator accordingly, thus avoiding voltage collapse resulting from extreme contingencies. The GLCC control solution was intensively tested in simulation using PSSE software. Moreover, a pilot project was commissioned on a test bench replica of the system and also tested in real time using Hydro-Quebec's Hypersim digital simulator. Field tests of the GLCC were conducted on a -230/+660MVars static vars compensator. The results of this pilot project were deemed conclusive and the deployment of the new voltage control system has been initiated by Hydro-Quebec.