Power/frequency characteristics of the British grid system

An account is given of tripping tests carried out to measure the power/frequency characteristics of the British Grid system for various conditions of plant and load. An equation is derived for estimating the power/frequency characteristics of the system from a knowledge of the turbine capacity on the busbars and the system load. The results of the tripping tests are applied to the problem of predicting the change in power transfer which would occur on a line connecting two large systems, as a result of a disturbance (in generationor demand) in either, from a knowledge of the difference between the frequencies of the two systems before the interconnection is established. Further series of tests were carried out to investigate whether the relationship between the changes in power transfer and the frequency differences would apply in actual continuous operation. It is shown that this relationship would apply for short periods or when the effects of manual control of the system are eliminated. For longer periods of manual control it is found necessary to use a reduced value for the power/frequency characteristic.