Abstract: Transaction of electric power has been conventionally conducted mainly to cope with power demand of a large-volume customer, and in which a power customer presents a power demand for covering a certain period of time, and power companies tenders for the offer. In this manner, the transaction was done in reliance on manpower.

Abstract: The power system stabilizer is provided at an individual power system to be separated due to an accident cutting off a link line which interconnects a number of power systems to form a large-scale power system. The power systems include power stations such as power plants and transformer substations. A simplified arithmetic processing unit of the stabilizer performs an arithmetic processing by a simple linear equation using an output frequency of a representative power station belonging to the separated power system immediately after the accident has been cleared, so that a total load drop of the separated power system can be assumed. Based on the assumption amount, balance control of demand and supply in the separated system is made.

Abstract: An abnormal signal detecting device, comprising a signal sampling and conversion circuit for sampling a predetermined number of data points along an analog signal and generating digital sampled data signals representative thereof; a memory circuit, connected to the signal sampling and conversion circuit, for storing the digital sampled data; and a consistency detecting circuit, connected to the memory circuit, for comparing at least three consecutive digital sampled data signals and generating an output representing an abnormal condition whenever at least three consecutive digital sampled data signals are the same.