In 2011, a FACTS undertaking comprising a STATCOM (Static Compensator) and an SVC (Static Var Compensator) was supplied and commissioned by ABB in the power transmission system of Transelec in Chile. The purpose of the installations was to bring about increased power transmission capability over the Central Interconnected System by means of raising the system stability for steady-state as well as contingency conditions in the grid.
The Central Interconnected System serves the central part of Chile and supplies power to about 90% of the Chilean population. Transelec S.A. is the main transmission operator and owns and operates transmission facilities at voltages from 500 kV down to 66 kV.
The growth of power generation in Chile has generally not been accompanied by corresponding increases of power transmission capacity. In Chile, as in other parts of the world, there is growing opposition to the construction of new transmission infrastructure. As a consequence, there has been increasing pressure to find suitable ways to exploit existing facilities to a higher degree. To this end, after completion of feasibility studies, it was decided to install FACTS devices at critical points in the grid with the aim of increasing the dynamic stability of the system and thereby allow more power to be transmitted through the grid.
The undertaking comprises the following items:
- A STATCOM located the at Cerro Navia 220 kV substation, rated at 65 Mvar inductive to 140 Mvar capacitive (-65/+140 Mvar);
- An SVC located at the Polpaico 220 kV substation, rated at -65/+100 Mvar.
- Control of an MSC (Mechanically Switched Capacitor) located at the Polpaico 220 kV substation, and rated at 100 Mvar.
The common tasks of the FACTS devices are the following:
- Regulate and control the 220 kV grid voltage under normal steady-state and contingency conditions;
- Provide dynamic, fast response reactive power following system contingencies, such as network short circuits and line or generator outages, particularly during high power flow from Ancoa northwards.
- Enable an increase of the power transfer capability of the grid.
Both Cerro Navia and Polpaico substations are located in the capital of Santiago de Chile, where the greatest part of the load of the Central Interconnected System is concentrated. Together, the devices increase the power transmission capacity from previously 1.400 MW to 1.600 MW over the 500 kV corridor between Ancoa and Alto Jahuel, and Ancoa and Polpaico, a transmission corridor exceeding 300 km of length