Transpower owns and operates the New Zealand national grid, a high-voltage transmission network that delivers power to industrial, business, farming, and domestic electricity consumers. Transpower must balance load and generation to keep the grid’s frequency at 50 Hz. If one generator fails, power from other generators must be made available within a few seconds to offset the loss and ensure the system frequency doesn’t fall to a level from which recovery is not possible.
Because it is costly to hold generated power in reserve, Transpower must precisely calculate the minimum reserve needed to ensure the reliability of the grid within established risk tolerances.
To meet this need, Transpower has developed the Reserve Management Tool (RMT) in MATLAB® and Simulink®. RMT includes a sophisticated model of the entire grid, including generators, loads, and high-voltage direct current (HVDC) links between New Zealand’s two main islands. Simulations based on up-to-the-minute grid information are run every half hour to determine the currently needed reserve.
“Transpower has two directives. One is to make sure the lights stay on by operating the grid reliably, and the other is to do this economically,” says Heidi Heath, investigations engineer at Transpower. “By driving Simulink simulations with real-world data, we not only make better tradeoffs between cost and reliability, we actually reduce costs while improving service.”