The problem
The state of Delaware in the USA has seen a steady growth in electric energy consumption, but also a significant increase in peak power demand. The power peaking typically on a hot summer scenario with the majority of the load being constituted by air-conditioning systems and units. In 1999 one power peak coincided with an outage of a large generating unit and a voltage collapse nearly occurred. The situation with heavy air-conditioning load is prone to voltage collapse as the induction motors in the air-conditioning units will draw excess reactive power at depressed voltages.
The solution
Following the critical event in 1999, the transmission owner CONNECTIV decided to assure that the problem could be avoided already the next summer. For this purpose CONNECTIV purchased an SVC to be installed at the NELSON S/S. The SVC is rated 100Mvar inductive to 150Mvar capacitive and connected to the station 230kV bus. ABB delivered the SVC in well under twelve months.
As some generating units have been or will be shut in the Delaware area, CONNECTIV has purchased two more SVCs from ABB, these units will assure the grid operation in the absence of the voltage support provided by the machines. One of these latter SVCs was purchased on a nine month delivery schedule. The DELAWARE example illustrates how FACTS can quickly be introduced to enable uneconomic generation to be closed, or to off-load generation from reactive power production.