Implementation of an optimal control scheme for MSC and SVC compensation

The National Grid Company of the UK (NGC) has embarked on an extensive program of installation of reactive power compensation to maintain margins from voltage collapse. Static VAr compensators (SVCs) and mechanically switched capacitors (MSCs) are being installed, each with local control schemes designed to provide response in the event of contingencies. A concern is that, while the introduction of high levels of reactive compensation does provide resources to prevent voltage collapse margins from being eroded, it also prevents voltage magnitudes from falling by any readily noticeable extent as collapse is approached. The network is more `brittle´ as voltage magnitudes give little indication of the margin of the system from collapse. A project has been initiated to develop and implement a facility to provide operator advice for the optimal management of this reactive compensation to ensure system security. Such a facility may lead ultimately to the closed loop control of variable reactive compensation