Hitachi Energy in collaboration with Red Eléctrica de España, Spanish TSO, has participated during the period 2010 - 2013 in the consortium TWENTIES (Transmission system operation with large penetration of Wind and other renewable Electricity sources in Networks by means of innovative Tools and Integrated Energy Solutions), that belongs to the FP7 EU program. The objective of the Project is to evaluate and integrate innovative grid solutions to increase the flexibility of transmission grids and maximize the amount of renewable energy in service.
TWENTIES has count on more than 26 European participants including utilities, research centers, universities and manufacturers among others. The consortium is divided in 6 independent demos, being demo 6 FLEXGRID the framework of Hitachi Energy involvement.
The project has been led by Power Grids division in Hitachi Energy Spain, in particular from the Power Consulting and Enginnering departments in close collaboration with SE Hitachi Energy FACTS department. The R&D Project aim to develop and install a new FACTS (Flexible AC Transmission System) prototype, called OverLoad Line Controller (OLC).
Hitachi Energy was directly involved in a diverse package of activities including Research on the new prototype, specification of equipment and implementation of the FACTS in the Spanish transmission grid. The solution is a new FACTS alternative with the objective to increase the flexibility of the transmission grid by redirecting the excess of power flow through an overloaded transmission line through other transmission lines with lower loading conditions. In this matter, the flexibility and control is improved minimizing the curtailment of renewable energy in service in the neighboring areas
The OLC is a series type FACTS solution rated 85 MVAr, installed at Magallón 220 kV substation in series with the transmission line Magallón-Entrerríos (360 MVA) rated. The solution combines traditional equipment, three parallel switched series reactors, and advanced control technology, Hitachi Energy MACH2. The control system evaluates and controls the load flow along the transmission line and is responsible to set the reactive compensation step to control the line impedance for normal operation and contingency operation of the system.
The OLC, commissioned at the end of May 2013, is presented as an attractive solution in terms of cost and functionality in comparison with other solutions in the market. Among the characteristics the following are remarkable:
- Innovative solution that combines traditional technology with advanced control systems, providing a quasi-dynamic control of the overhead line impedance.
- Modular solution based on standard equipment
- High response rate with ability to control power flows in steady state and contingency operation
MACH2 control system integrates several functionalities, among others zero crossing synchronized switching function - Capability to work in local and remote mode of operation, based on predefined references or set-points send by the system operator via tele-control. Additionally the possibility to work in emergency operation mode as backup system protection
- Control mode flexibility addressing TSO dispatch specific needs. The controls implemented in the prototype include: fixed impedance, power flow regulation, power flow limitation, maximum impedance compensation and emergency control