DEVELOPMENT OF AN MICROPROCESSOR BASED DATA ACQUISITION SYSTEM FOR SUBSTATION AUTOMATION

DEVELOPMENT OF AN MICROPROCESSOR BASED DATA ACQUISITION SYSTEM FOR SUBSTATION AUTOMATION

Abstract:

In high voltage transmission systems fault levels are generally high, which if not cleared rapidly can cause system instability as well as extensive damages and hazards to personnel. Speed of operation, selectivity, reliability and security of the trip decision assume more importance at higher operating voltages as they handle bulk of the power. Data Acquisition is the prerequisite to achieve the above stated objectives. The paper deals with the designing and assembling of architecture, both hardware and software design for data acquisition for automating a substation. A scaled down model of a substation has been developed in this regard. The hardware mainly consists of signal processing and data acquisition. An Intel 8086 microprocessor has been used to acquire data. Software, developed in 8086 language, is written in modules for easy understanding and implementation. This program acquires data like bus voltages and line currents from the system. In order to demonstrate the use of data acquired we have developed a simple fault detection scheme using over voltage and over current criteria. When a fault signal is detected, the processor sends a trip signal to the appropriate circuit breaker to isolate the faulted component from the system. The program also calculates the power factor of the load present in the system. Possibilities of future developments to improve the design and performance of the data acquisition schemes have been discussed.

Introduction:

Substations are switching and transforming stations, located between generating and load centers. A modern substation is a complex structure, as it requires numerous items of equipment and allied service. This equipment provides supervision, control and protection of substation. In a typical substation, the control equipment can be either analog or digital in nature. Their operation can be either manual or automatic. In either case, the control equipment gives commands to circuit breakers to perform duties
such as switching, auto reclosure, bus bar protection etc. With the increase in the complexity and size of the substation, automatic control or the automation of Substation has assumed great importance.


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