The Optical Fiber Electric Energy Measuring Equipment Of Zero-voltage Drop

As the processing of the national electric power systems,accurate electricity computation has important meaning to the calculation of electricity generating and supply ,the integrated balance and examination of economic technical index of system of electricity ,energy saving and reasonable collection of electricity fee,etc.At first,the paper introduces the composition principle of Electric Energy Metering Device and analyzes the comprehensive error of it.The synthesis errors in the electric power measuring equipment include these of the ammeter,transformer and these caused by the secondary circuit voltage drop of the transformer.All these errors are mainly caused by a far distance between the outdoor voltage transformer and indoor ammeter,which is connected by such units as the sencondary contact wires,switch,fuse and terminal block.Their uncertain contact resistance can cause a voltage drop in the secondary circuit which is a dynamic variable.Then the paper analyzes some methods which is used to reduce the energy metering error caused by the secondary circuit voltage drop of the transformer.The traditional ones are to compensate for the current drop caused by load changes without changing the resistance of the secondary circuit.This method may be less or over compensated which can not reach the purpose of measuring the electric power exactly.Aiming at these problems,this paper put forward a new method of the electric energy measurement.That is the electric energy measuring method of zero-voltage drop using optical fiber,it converts the analog voltage signal that is the output of voltage transformer into the digital signal and converts it into optical signal.At the same time,it is transferred to the indoor control room and changes it into analog voltage signal which is input to ammeter.This paper analyzes signals acquisition,transmission and reduction.This equipment make the secondary circuit voltage drop of voltage transformer become zero,that is to say,the amplitude of input can be well followed by that of resistance. Through this way we can solve the problems existing in the compensating equipment and reach the standard.At the end of this paper,The temperature performance and stability are verified by the test,the test results of ratio error,phase error and the error of the electric energy measurement are given and analyzed.At the same time,this equipment has run and the result is very good.