In recent years, with the rapid development of China’s
power industry, power transformers is hair, transmission, transformation and one of the important equipment in the distribution system, its performance, quality is directly related to power system reliability and operational efficiency.
The power transformer is one of the core equipment of power system operation, therefore, safe and reliable 110kv power transformer operation is the fundamental guarantee for the normal operation of the power system.With the increasing of the capacity of the transformer, the transformer loss will also increase, and the tank wall and the radiator alone can’t meet the cooling requirements, requires the use of sub-cycle air-cooled or forced oil circulation wind, coolers, cooling and then pump back to the transformer.Large-capacity transformer has been oriented cooling, has acertain amount of oil in the winding and core internal to enter the cold oil in the fuel tank all the internal outflow through the winding and core, so that took away a lot of heat, you can increase the cooling efficientcy. Transformer cooling system determines the normal life of the transformer cooling system safe and economic operation of the transformer and of great importance.In power plants or substations, air-cooled transformers with multiple fan cooling, control transformer oil temperature within the rated range, to ensure the normal working of the transformer. In order to improve the reliability of power system operation and extend the life of the transformer, the transformer oil temperature real-time monitoring.
At present, there are many transformers are collected by the electric contact thermomter, showing the transformer oil, to control the fan start and stop, transformer oil, to control the fan start and stop, transformer temperature control in the actual operation, due to the fan start when fully operational, while all the stops, the impact of current seriously affect the life of the motor. And inabailty to contact and control room,it is not possible to achieve unmanned control of the transformer, an increase of operating costs. Transformer thermostat there is always some problems, such as measurement error, and poor antiinterference ability, these are the very difficilt problem in engineering. The temperature controller of the early , bulky and complicated to operate , poor anti-interference ability , to the use of the project site has also brought a lot of inconvenience . Microcontroller technology continues to evolve , the temperature controller forward monolithically integrated , intelligent direction to develop rapidly. Intelligent temperature control system, the problems of power transformers during operation , can be used to achieve the automatic acquisition of the temperature show that the order of the fan starts and stops .
According to site operational requirements , the design selection of the PIC16F877 MCU constitute the transformer temperature control system , the equipment is simple ,user can easily set up through the panel buttons to control the fan starts and stops, alarm and trip thresholds, all the set parameters aren’t after power lost. The temperature acquisition accuracy is high, and has taken many measures to protect the motor, such as overload, phase loss protection.
Due to poor industrial environment in the field, the system will generate a lot of interference, designed to take thr anti-jamming measures, increase in the IC’s power supply at the entrance to the filter capacitor, the signal into the microcontroller through the optocoupler isolation. Finally, wireless communications, remote monitoring, control room through wireless communication to grasp the scene of operation, can be arbitrary to make a variety of accidents in atimely manner to reflect the unmanned control of the transformer. Measurement error is small, high resolution and strong anti-interference ability of the system as a whole, the choice of all devices meet industry-standard and is suitable for high temperature environment.
As a result of the above mersures, to ensure that the control system stability, the design has good scalability meet the requirements of the vatious models of the transformer.
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