Measurement of voltage phase for the French future defence plan against losses of synchronism

A sure way of detecting loss of synchronism is to measure the rotation of the voltage vector at various points on the grid. Electricite de France plans to use this method to detect loss of synchronism on the French EHV network. The authors describe some of the work which has been undertaken in order to perform local measurements of voltage characteristics such as phase. Particular attention is given to the hypotheses adopted concerning signal modeling, definition of magnitudes and parameter variation; a review of existing calculation methods (zero-crossing algorithm, FFT, etc); the search for a new type of algorithm; the implementation of this algorithm using 16-bit signal processors; and experimentation on the future defense plan. The first stage of the plan, covering the South-East and Alps region of the French network, is to come into service in 1994. >