Applications of new technology in power substations
The authors describe the applications of some of the more modern technologies to instrument designed specifically to operate in utility substation environments. Particular emphasis is placed on the use of CMOS logic, processor, and memory circuits, high-density flexible magnetic disk media, and high-capacity Winchester technology storage devices. The operating history of a number of units over a five-year period is reported, as well as the steps taken to protect these devices in a hostile environment. In addition, areas requiring specific improvement and adaptation are noted.<<ETX>>
A proposed application of an industrial DOS computer for distribution substation monitoring and control
This paper presents the design and implementation of an intelligent controller intended for use in distribution substations to perform monitoring and control duties within the framework of distribution automation needs. The hardware of the developed controller is a DOS based industrial computer running on ECB-BUS. The application software handles all input/output tasks, data collection, manipulation and control design decisions with its flexible structure. This embedded controller measures bus voltage, transformer and feeder currents and calculates the real and reactive power, power factor, frequency, and total harmonic distortion of voltage and current. In addition to its local remote data acquisition and monitoring functions by means of console and SCADA outputs, the system, through its relay outputs, is capable of performing automation tasks such as integrated Volt/VAr control, overload and underfrequency detection and load shedding at the substation level. This reliable, high capacity and low cost system is completely programmable so that it can handle new requirements with new configurations easily. >
Prediction of electromagnetic field and current transients in power transmission and distribution systems
A time-domain model is described for predicting transient bus currents, electromagnetic fields, and cable-coupling effects caused by switching actions in high-voltage substations. Having been validated against measured transient data, the model provides a basis for predicting EMI effects resulting from abnormal switching actions, such as phase-to-ground faults, which are difficult to stage for measurement. From such worst-case estimates, the adequacy of the latest standards for microprocessor-controlled substation protection can be assessed. >