Tehnička biblioteka

Reducing the risk of failure on high voltage instrument transformers in the transmission system using the application of narrowband dielectric frequency response (NB DFR) on HV CVTs.

This is an easy solution to measure the impedance values for cables, the values are used for calculation of compensation factor in distance protection.The compensation factor is first theoretically calculated and these values can now be compared with the measured values.

The test and maintenance of electrical components on rolling stock is not an easy job to do. Some maintainers dismount some of the parts and bring them to a central location for revision and maintenance. This is a cumbersome and time consuming exercise. In many cases, the electrical parts are replaced only when they break down and are not subject to periodical testing. This of course holds a risk as some parts, e.g. circuit breakers, are crucial for safety reasons.

The Power Grid Corporation of India Limited (PGCIL) is an Indian state-owned company headquartered in Gurugram (North India) engaged mainly in Trans-mission  of  Power  and  transmits  about  50%  of  the  total  power  generated  in  India  on  its  transmission  network.  The  company  owns  and  operates  about  1,61,790  circuit  kms  of  transmission  lines  at  800/765 kV,  400 kV,  220 kV  &  132 kV EHVAC and +500 kV HVDC levels and 248 sub-stations. Also, it has the transformation capacity of about 396 825 MVA as of 30th November 2019.

When measuring very low resistance the four-wire test method has for many years been the standard method. The main advantage being that it simply and easily removes the resistance of the test leads from the measurement. However, what happens when those test leads need to be verylong?

Introducing the first low resistance ohmmeter to feature a difference meter, a device that turns changes in resistance into a moving pointer and percentage change. When testing multiple similar connections, it makes it easy to spot those small increases in resistance that eventually turn into major faults.

Safety warnings for DLRO2

When performing calibration verification of the TTRU3, the following factors need to be considered to achieve accurate measurements and prevent damage to your calibration fixture or TTRU3.

REQUIREMENTS FOR SAFE WORK ENVIRONMENT WHEN PERFORMING MV or LV POWER CABLE FAULT LOCATING BY DISCHARGING A HIGH VOLTAGE CAPACITOR.

Since the 1950’s vacuum has been used as insulation media in switchgears. Even though that technology has proven to be very reliable, over time air will leak into the vacuum chamber and degrade the insulation. Also, a good practice is to measure after transport or accidents. The accepted way to test the vacuum integrity has always been through a voltage withstand test. For field tests DC test is preferred due to the weight andsize of the instruments.