The Design And Application Of The Smart Grid Transformer Cooling System

Construction of the smart grid is an arduous historic engineering,and intelligent substation running is the one of the most basic step to realize the smart grid.Intelligent substation can be divided into the control layer,spacer layer and process layer.Power transformer which is one of the most important in the process layer high voltage equipment has a high accident rate,fault impact big shortcoming.Therefore it has a great influence on the reliability of the power grid.The transformer cooling system is the important guarantee for normal operation of transformer can be.At present,the transformer cooling system widely uses conventional relay logic control unit.The main existing problems are: complex wiring,maintenance difficulties.High failure rate of relay impede the normal operation of the system.The system can’t collect complete operational data,therefore can’t achieve all the information monitoring.The system can’t automatic remote monitoring,intelligent low,and people’s workload is huge.It can’t timely adjustment of temperature,resulting in a waste of energy,while reducing equipment life.In view of the existing equipment more than disadvantage,the purpose of this paper is to develop a new type of cooling system,and on the basis of the system realize the fuzzy PID control of the temperature of transformer.Not only can simplify the circuit and improve the system reliability and save energy,also can realize intelligent control of transformer temperature.This article main research content is as follows:(1)The study of transformer cooler.First study the different capacity of transformer cooling mode and its ways to heat.Then analyze the structure of the cooler,mainly including the cooler body and accessories.After that,set transformer temperature rise limits of each part,and the calculation of oil,windings for air,oil,air and oil below average temperature rise.Finally,set the performance parameters of the cooler.(2)The construction of the transformer cooler hardware system.In order to realize the intelligent monitoring of the cooling system,use the reliability of the technology,the remote monitoring system,intelligent control algorithm,and indicate the system can realize what kind of function.According to the actual control need write I/O table and select the model of required modules.Choose electrical component model,then design the motor protection control wiring diagram,and PLC input/output connection diagram.According to the principle of wiring diagram introduce the realization way of all components function.(3)The design of the fuzzy PID compound controller.First of all,on the basic of principle and characteristics of PID control and fuzzy control,design the control device.With transformer top oil temperature and the temperature difference of a given temperature E,temperature difference rate of change EC as input,use fuzzy controller on-line adjusting PID control of the three parameters KP,KI and KD,so as to control the cooler frequency,to realize the optimization of the cooling frequency conversion design.At the same time,through the MALTAB simulation,we can see the control effect of fuzzy PID compound control is superior to the control effect of PID controller.(4)The design of the transformer cooler software system.First design PLC monitoring software program,and design the system main program and subroutines.Then achieve corresponding fuzzy PID control algorithm based on the software STEP 7.Finally complete the design of the PC monitoring software,so that the PC is better under the monitoring and management of a machine.