The Design Of Transient Earth Voltage Detector Based On Cortex-M3

Switchgear is the main electrical equipment of power system,Its operation is directlyrelated to the safety and stability of power system operation. In recent years,Because of therapid transformation of economic industry, The requirements of power quality isimproving of New electronic products, as well as the national, So we have to reduce thegrid power without any warning to ensure the safely and stably operating of power grid. Inthe development of the power system, the development direction of power grid is the largercapacity and miniaturization, this makes the insulation degradation of the switchgear to bemain causes of partial discharge. So, in order to reduce the economic loss brought by thepartial discharge, partial discharge monitoring system are put forward.Partial discharge is the electric discharge phenomena,which is the filed intensitygenerated by impressed voltage in electrical equipment,result in discharging in theinsulation area,but unable to form the fixed discharging channel in this area.Currently,theconventional partial discharging detecting method includes the ultrasonic method,thetransient ground voltage method and the infrared thermal imaging method. The generalpartial discharge is measuring the apparent discharge capacity which is measured inhigh-pressure discharge,but the transient ground voltage method measures the amplitude ofthe discharge pulse not the apparent discharge capacity.This method can reduce theinterference to some extent.Because of the characteristics of the switchgear,the paperselects and uses the transient ground voltage method as the research method. Theacquisition of signal of transient ground voltage method mainly utilizes the capacitivecoupling module which is stick to the ektexine of switchgear,which can coupling theelectromagnetic wave by partial discharge,and gathering the partial discharge signal.Inorder to filtering the interference,the gathered signals need to be filtering firstly. The filtercircuit selects Voltage-controlled voltage source second-order bandpass filter.Because thepartial discharge signals are weak in some extent,the signals must be into the amplifyingcircuit after filtering.This paper designs a partial discharge on-line monitoring system, because of rapidlydeveloping of the embedded system, so we choose the embedded system. The first isa summary of embedded system,and some basic introduction of the composition andapplication.And then developing the embedded system,which include the developing ofsoftware and hardware. Software part is mainly the signal acquisition and processingsystem and the design of the key circuit. The hardware part is mainly the design of eachhardware module,including power supply module, clock module, A/D conversion circuit and so on. The system chooses STM32F103VET6as the micro controller of the system,which has small volume, low power consumption, low cost and so on.Experimental results show that the designed system is feasible. The design oftransient earth voltage detector based on Cortex-M3has certain advantages on powerconsumption, stability and can expand sex,which has a broad space for development...