| As electrical equipment, power transformer is widely used in power systems and enterprise users. It contacts network, converts the power supply network voltage to voltage that electrical equipments or devices can use directly and plays a key role in power transmission, distribution and use process. Transformer cooling control system is an important part to ensure its safety of normal operation. The traditional transformer cooling control system, due to the control system consisting of logic circuit of mechanical contacts, high security hidden hazards, low automatization, cannot adapt to the needs of today's unattended substation, so the new control system design is imperative. For the existing transformer cooling control system has many shortcomings, such as the complicated system control circuit, the low reliability, protection methods of fan being so simple, large control error, high fault rate, massive maintenance work and no method to realize remote communication, this paper develops a novel intelligent transformer cooling control system based on the center of microprocessor through all-round technology analysis and research. This system has full use of software resources, while ensuring the reliability of control system based on the hardware circuit as simply device , completely abandon the relay logic approach, improved the function transformer cooling control system. Transformer top oil temperature and system load and other parameters as the amount charged, by a margin of the vote delay, cutting the temperature threshold of the control strategies and the cumulative time fan automatically balanced by switching the fans control method to achieve automatic control of fans. In addition, the main circuit uses non-contract AC solid-state relay (SSR) to control fans'input and cut off instead of A.C. contactor. SSR has high switching off speed avoiding contract burned to shut down fans. This system can overcome the defects of traditional transformer cooling control system, such as logic control dysfunction, inconvenience expansion, poor contact and so prone to abuse. As its comprehensive functions, easy expansion, easy maintenance, safe and reliable operation, it achieves automatic control of air cooling system. So it is the ideal alternative of traditional transformer cooling control system with engineering applications value. |
