6.4 High Voltage Phase Detector
In the construction or maintenance of the power system loop network and dual power supply power network,phase inspection of the power supplies on both sides of the closed-loop point circuit breaker is a very important test item,otherwise interphase short circuit may occur,causing terrible consequences.
1.Basic Structure and Function of High Voltage Phasing Tester
(1)Basic structure
①The high-voltage phasing tester consists of three parts:two voltage detection and emission combined devices(including insulating rod)and a wireless receiving device.Fig.6-22 shows the structure of the HV phasing tester.
②The two transmitting devices respectively send the sampled voltage data signals to the receiving end through the high-frequency transmitting device,and the receiving end carries out corresponding processing according to the signals transmitted by the transmitter,and displays the phase relation and the frequency of the two lines on the display screen.
Fig.6-22 Structure of HV Phasing Tester
1-Contact electrode;2-Emitter;3-Insulating rod;4-Receiver
(2)Basic function
Perform phasing operation on power lines.
2.Classification and Technical Specifications of Hv Phasing Tester
(1)Classification
①According to the working principle of phasing meter,HV phasing meter can be divided into capacitive phasing meter and resistive phasing meter.Capacitive phasing detector is used to detect and indicate the equipment based on the phase relation of current grounding through stray capacitance.It has two types:double-pole unconnected lead and single-pole memory system.Resistive phasing meter is used to detect and indicate equipment based on the phase relation of current passing through resistive elements,such as double-pole phasing meter.
②According to the type of phasing meter,it can be divided into single phasing meter and split phasing meter.
(2)Technical specifications
①Use range:6-35kV.
②Maximum distance between transmitters:20m.
③Insulating rod:2 pieces with 4 sections in total.When in use,the two sections shall be jointed.The insulating rod is made of epoxy resin.
3.Inspection Contents of Hv Phasing Tester
The HV phasing tester must be inspected before use as follows.
(1)Check whether the appearance of the HV phasing tester is good.
(2)Check the factory certificate and calibration certificate of the HV phasing tester and confirm that the HV phasing tester is within the inspection period.
(3)Check the insulation rod withstand voltage test report.If there is no qualified insulation rod withstand voltage test report,it cannot be used.It is forbidden to use the HV phasing tester in rainy days.(https://www.daowen.com)
(4)Check whether the meter battery is in good condition and charge it before use.
(5)Before phase test,check whether the phasing tester is normal on the same power grid,with one person for operation and one person for monitoring.Fig.6-23 shows the inspection of HV phasing tester,and Fig.6-24 shows the inspection of insulation rod of HV phasing tester.
Fig.6-23 Inspection of HV Phasing Tester
Fig.6-24 Inspection of Insulating Rod of HV Phasing Tester
4.Usage of HV Phasing Tester
(1)Connect the transmitter and insulating rod before use.
(2)Check the phase.Hook the metal of the phasing tester main pole(with meter pole)to any phase of the live A-side line(the meter is with indication in this case),and connect the other pole(auxiliary pole)to any phase of the B-side line.If the meter indicates zero or close to zero at this time,the phases of the two lines of the tested line are in phase.When the pointer of the watch indicates the potential difference(line voltage)between the two outputs,the two phases are out of phase.
(3)Check the electricity.According to the phasing tester assembly,the main pole is connected to the high-voltage line,the auxiliary pole is grounded or connected to the iron cross arm,and another wire can be connected.If the indicator value is large,it indicates that the line is charged,otherwise,it is not.
(4)When checking on grounding fault.In the power system with neutral point not directly grounded,it can be used to locate the grounding point,connect the main pole to the line of grounding accident,and connect the auxiliary pole to the grounding wire and metal frame or cross arm.At this time,the meter will indicate zero.When a device with accident is disconnected,the indicating value of the meter will be large,and the grounding will be eliminated.
5.Precautions for Storage of Hv Phasing Tester
(1)The HV phasing tester shall be stored in a well-ventilated,dry and clean environment,and put on shelves.
(2)Properly maintain instruments and apparatus.
(3)Properly keep technical data and instructions of instruments and apparatus.Fig.6-25 shows a tool cabinet for storing HV phasing tester.
Fig.6-25 Tool Cabinet for Storage of HV Phasing Tester
6.Preventive Test of HV Phasing Tester
The types of preventive tests for HV phasing tester are as follows.
(1)The HV phasing tester shall be sent for inspection on a regular basis.
(2)The HV phasing tester shall be regularly checked.
(3)The insulation rod of the HV phasing tester shall be subjected to pressure test regularly,and the period of pressure test of the HV phasing tester shall be half a year.