The Kiisa power plant forms part of Estonia’s emergency reserve, which means that it only operates when there is a network failure or capacity shortfall. The plant is operated by Elering, the Estonian Transmission System Operator (TSO), and is located in the northern part of the country. It was supplied by Wärtsilä, a Finland-based power solutions provider and long-term partner of ABB. In addition to the generators, ABB’s scope of supply included automatic voltage regulators, control systems with protection relays, substations and special SCADA (supervisory control and data acquisition) process control systems.
ABB worked closely with Wärtsilä to design innovative solutions. The plant had to meet a number of rigorous requirements including the ability to ramp up to 100 percent load in less than 10 minutes from standby mode, as well as blackout capability. It is fully automated, which means no permanent personnel on site is needed. Another technological challenge was posed by the grid code requirement for a 250 millisecond fault ride-through time. To achieve this, the generators’ inertia had to be increased.
The gensets at the Kiisa plant are independently controlled and designed for dual-fuel operation using either natural gas or diesel. This provides additional flexibility and redundancy.
The plant’s capacity covers one sixth of Estonia’s peak power consumption, and is sufficient to meet the power requirements of the nation’s capital, Tallinn. It is kept on constant standby in case a problem occurs somewhere in the network. Power consumption in standby mode is only around 200 kW.