Research On The Wind Cooling Control System Of Transformer Based On PLC

The electric power is the important secondary energy source and is crucial to the national economy developments. The power transformer, as the extensive use of electrical equipments for the electric power system and enterprise customers, integrates all of the facilities into a electric network, transfers the supply network voltage into the service voltage for the utilities of all kinds of equipments and devices. It plays a pivotal role in electric power transmission, allocation and application. Anyway, it is the wind cooling control system of the transformer, the important portion to this instrument, that ensure the transformer and the electric network run normally and safely.The traditional transformer wind cooling control casing still remains at the technological level of 20th century 60th. At the same time, the control system is composed of mechanical contact logic circuit, yet it is not safe, at low automatic level and can not be achieved unattended. Consequently, it is imperative to improve the original design.For the problems being in the wind cooling control system of the traditional main transformer, such as the complicated control circuit, low reliability, high fault rate, large control error etc., this paper brings forward a new design based on PLC of the principle and implementation of a transformer's wind cooling control system.The S7-200 PLC of Siemens is the core of the new design. Based on this, the new system can achieve a variety of functions of the wind cooling control system. The new control system considers the top oil temperature and load of the transformer as its controlled variables, and uses control strategy of switch on and off values, which have margin in them. And the model combines the cumulative running time and the cumulative stop time of the cooling system, to realize the balanced integrated auto control of the cooling device. Besides this, the system has other functions such as communication, remote surveillance, fault locating etc. In addition, the main circuit uses non-contract solid module, which has the characteristics of high speed switching off, and thus can avoid contract burned to stop blower cooling device. And it chooses electric-engine protector to protect fan and oil pump motor other than heat protector. The electric-engine protector has many advantages such as high reliability, low fault rate, easy to install etc.The new design which is the ideal updated product of the traditional wind cooling control system can overcome almost all kind of shortcomings of the traditional wind cooling control system such as low features, hard to expand, bad connection etc.And the wider use of the new system will be of much more help to ease increasingly growing energy resource crisis, to promote effective allocation of resources, to reduce noise pollution, and to speed sustainable economic development healthily etc. And it will also be of practical and profound significance to today's society.