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Transformer Testing


New York's Path to 8.5 GW of Grid Flexibility by 2040

New York State's transition to a clean, zero-emissions energy grid could include up to 8.5 gigawatts (GW) of grid flexibility by 2040, according to a new report from the Brattle Group. This projection, while contingent on achieving ambitious decarbonization goals, illustrates how the state could...

Dielectric Voltage Testing – Standard Methods

There are two standard methods from ASTM International: D877, Standard Test Method for Dielectric Breakdown Voltage of Insulating Liquids Using Disk Electrodes, and D1816, Standard Test Method for Dielectric Breakdown Voltage of Insulating Oils of Petroleum Origin Using VDE Electrodes. VDE stands...

Breaker Testing


Partial Discharge & Circuit Breaker Asset Management

Detecting and avoiding preventable failures BY JAY GARNETT, Doble Engineering Company While metal clad switchgear can be very reliable, sometimes operating for over 50 years, throughout the aging process, this group of electrical disconnect switches, fuses and circuit breakers can experience...

Dynamic Resistance Measurement

Condition testing of circuit breaker’s arcing contacts BY BUDO MILOVIC, DV-Power The preventive maintenance on a high-voltage (HV) breaker consists of several routine tests. The timing and motion tests are methods used to assess the breaker’s mechanical condition. When the timing and motion...

Cable Testing


Solving Underground Cable Problems with Partial Discharge Testing

How to prevent failure with partial discharge testing BY HENNING OETJEN, Megger Partial discharge (PD) measurements are increasingly used as a reliable and non-destructive diagnostic method to detect weak spots in the insulation of underground cables. Routinely, partial discharge measurements are...

HV Test Equipment

Zensol new instrument for OLTC testing

According to CIGRE A2.34, the dynamic resistance measurement or DRM (OFFLINE) is a test that offers diagnostics for several diverter or selector switch malfunctions such as: contact problems, broken springs, broken transition resistors, poor contact pressure, inadequate transition time, momentary open circuit, and synchronism motion issues.

Zensol’s DRM principle

Tap windings are powered with a DC voltage source. The current fluctuations are recorded during the switching process. The schematic below shows the principle of the...

HV Test Equipment Articles