Why transmission planners and protection engineers need to work more closely together.
Diwakar Tewari (tewarid@saic.com) is a senior consultant at SAIC. Previously he was manager of operations engineering at California ISO, and team leader in transmission access planning at the Midwest Independent Transmission System Operator (MISO).
The three Ps of power system reliability are planning, protection and performance—and they’re interrelated. Transmission planners are responsible for planning the transmission system and studying future transmission system conditions to ensure that it’s capable of handling anticipated needs. Future load growth, generation additions, transmission expansion, reconfiguration and changes in protection schemes are some of the key elements affecting grid reliability, and therefore a comprehensive reliability evaluation is needed on a periodic basis. The North American Electric Reliability Corp. (NERC) transmission planning (TPL) standards are guiding principles for transmission planners for conducting such evaluations. The standards require assessment of system conditions in near-term and longer-term planning horizons under various contingency conditions to ensure the transmission system can survive all credible single-element disturbances without loss of any firm demand. The purpose of planning studies is to catch any potential reliability issues well in advance, so that proper mitigation measures can be implemented before an outage situation or crisis arises.