PLC power supply and safety (emergency) circuits requirements

The source for a PLC power supply is generally single-phase and 120 or 240 VAC. If the controller is installed in an enclosure, the two power leads (L1 hot and… Read more

Mar 15, 2017 | Edvard

Performing power factor test on dry-type transformer during commissioning

The power factor test is a maintenance test used to determine the insulation system dielectric power loss by measuring the power angle between an applied AC voltage and the resultant… Read more

Mar 01, 2017 | Edvard

Measurement of N–PE loop resistance in TN, TT and IT systems

Up-to-date test instruments, with built in modern electronics, can measure loop resistance even between the neutral N and protection PE conductors in spite of possible high currents in the neutral… Read more

Feb 24, 2017 | Edvard

Guidelines for high potential (Hi-Pot) DC testing of medium voltage cables

This technical article provides general guidelines for high potential “Hi-Pot” DC testing of MV power cables. All tests made following cable installation and during the warranty period must be performed… Read more

Feb 20, 2017 | Edvard

The easiest way to measure ground resistance using clamp meter, but be carefull!

The ground clamp meter / tester is an effective and time-saving tool when used correctly because the user does not have to disconnect the ground system to make a measurement… Read more

Feb 06, 2017 | Edvard

Transformer exterior inspection and tests you MUST perform periodically

Periodic transformer exterior inspection (visual) reveals important condition information. For example, valves positioned incorrectly, plugged radiators, stuck temperature indicator and level gauges, and noisy oil pumps or fans. Oil leaks… Read more

Jan 25, 2017 | Edvard

Commissioning of protection relays using test equipment and software

Commissioning and maintenance With numerical protection relays commissioning and maintenance has become far less complicated as a result of the information provided by the devices as well as the integrated… Read more

Jan 16, 2017 | Edvard

Troubleshooting dead circuit by testing continuity with disconnected supply

Dead circuit testing is testing performed with the power disconnected from the circuit. The main benefit of disconnecting power supply while tests with an external energy source are performed is… Read more

Nov 28, 2016 | Edvard

3 good ways to improve earth electrode resistance

When you find that your earth electrode resistance is not low enough, there are several ways you can improve it: Lengthen the earth electrode in the earth Use multiple rods… Read more

Nov 25, 2016 | Edvard

High voltage station – Design, construction and commissioning process

Having selected the right site location for high voltage station, the design construction and commissioning process would broadly follow the steps shown in Figure 1. Recent trends in utilities have… Read more

Nov 11, 2016 | Edvard