Design Of Grounding Device Parameters Measurement System Based On GPS Clock Synchronization Shunt Test Function

The grounding system is one of the most important parts to guarantee the safe and stable operation of the power system,and to ensure the safety of power system operation personnel and electrical equipment.With the continuous improvement of voltage grade,there are more and more of high voltage transformer substation,especially with the EHV and UHV substation construction and putting into operation,the grid structure and the structure connected to the grid are more and more complicated.If it is unable to accurately assess the shunt condition of diversion structure,it will lead to the user can't obtain the real value of grounding impedance of the grounding grid on site.Therefore it is necessary to measure the shunt of outlet and inlet line wire architectures;So that we can correct the grounding impedance value we test.The traditional theoretical to calculate the shunt has insufficient in complicated calculation process,hard to get parameter values and practicability is poorer.The shunt is used to as a scalar to measure and calculate.But due to the inlet and outlet wire structure contain inductive component,the shunt of the wire frame present phase angle difference with the injection current,they are not always the same or the opposite,so it can't directly to add and subtract the value of shunt.Besides,there is a way to test the shunt phase angle that based on the wireless signal transmission techniques,which is easy to be influenced by the test environment of the scene.The strong electric field disturbance and obstacles of the scene will affect the wireless signal transmission quality,and limit the effective transmission distance of wireless signal.This paper carried out the design and development of grounding device parameters measurement system that is based on the GPS clock synchronization shunt test function.The research contents include: the pilot frequency testing principle of grounding device characteristic parameters tests,the influencemechanism of the shunt to the ground impedance test on-site,the principle of GPS clock synchronization shunt testing,and the design of a measurement system of grounding connection parameters with GPS shunt current test function and its field application.This paper designed a set of software and hardware test system which is suit for field application.Test system realizes the accurate test of the shunt vector.by adopting GPS clock synchronization shunt test technology,and using the high precision flexible ROGOWSKI current coil.Besides,it can effectively restrain the interference effects by adopting digital band-pass filtering technology.At last,this paper has verified the comprehensive performance and practicability of the software and hardware platform by using it to measure and analysis the parameters and shunt condition of a 500 kV converter station and two 220 k V substations grounding grid.The subject of research can provide with scientific reference basis to the large grounding grid running status diagnosis.It is of great significance to ensure the normal order of the grounding system even the whole power system reliable operation.So it may have huge economic value and social benefits.