The Dehumidifier Design Of The Switchgear Based On The Semiconductor Refrigeration Technology

Currently,the dehumidif ication system of the high voltage switchgear used in the power system is the heating type.It means that heating control system will start when environmental hum idity in the switchgear cabinet reaches a certain value.Afterwards,the heating plate is electrified,which makes air and the moisture in it be heated.The disadvantage of this system is that the water in the air will gather around the switchgear top and also the iron area of the switch.The water drops will fall down when it reach es certain weight,which may result in great safety risk for the power system equipment in the cabinet.Especially in the southern island region,where the air contains more salt content,water dripping down the equipment can easily cause corrosion and creepage phenomenon,which may result in short-circuit or power failure of the power plant equipment.In addit ion,the environmental temperature is also an important factor affecting the normal operation of electrical equipment,whose temperature will correspondingly increase along with the temperature changes of the environment,accelerating the insulation aging of some electrical equipment and even burn the insulation in severe cases.In this paper,firstly,various dehumidif ication technologies are generally discussed and the overall air flow characteristics in the high voltage switchgear are analyzed.On the basis of that,we choose the semiconductor condensing dehumidification technology to solve the dehumidif ication problem of the switchgear in the island transformer substation.Semiconductor condensing dehumidification technology is based on the electrical characteristics of the semiconductor and achieves the dehumidif ication effects by cooling the water contents in the environment to condensation temperature below.Compared with the traditional heat ing dehum idif ication technology,the condensing dehumidif ication technology has higher stability and smaller size,without the need of refrigerant and desiccant.It has shown great advantages and becomes more and more popular.Secondly,this paper designed the hardware and software of the semiconductor dehumidifier condensing dehumidif ication system based on the field investigat ions.The humidity sensors are used to monitor the environmental hum idity within the switchgear cabinet.The monitoring results are transmitted to the AVR m icro controller in real t ime,which can control the semiconductor dehumidif ier to start or stop,and drive the rotation of the fan.This process can condense the water inside the cabinet to the cooling area of the semiconductor dehumidif ier and discharge it out of the cabinet once the water condensation purpose is achieved.This control device can accurately monitor the relat ive hum idity of the air inside the high-volt age switchgear and can also reliably start the operation of dehumidifier.The condensing dehumidificat ion system solves the problem of traditional heating dehum idif ication system in which water contents flows up,and can condense the water down to the cabinet bottom completely.Finally,we’ve finished the on-site installat ion and testing of the semiconductor dehumidifier condensing dehumidification system.The experiments showed that the dehumidifier adopted the semiconductor refrigeration technology can effectively reduce the relat ive humidity of moist air,and it has important role and significance to ensure the operation and effective insulat ion of electrical equipment in high voltage switchgear,and to guarantee the safe and stable operation of local power system as well.