Medium-voltage cables are an integral part of modern power systems and have existed for over 100 years in various forms. Over the past 50 years, extruded cables have largely displaced paper insulated cables. Extruded cables offer many advantages over older designs, but are similarly prone to failure. Such failures are a significant impediment to improving overall power system reliability. Since …
With an ever-growing demand for a more reliable distribution grid, utilities are constantly looking for possibilities to optimize their distribution networks by implementing distribution automation. One method to improve the network and reduce permanent outages is using pole-mounted reclosers, due to their wide range of functionality. By introducing built-in voltage sensing on both source and load sides, automation can easily …
Coming up through the ranks in the power industry, I quickly realized I didn’t know what I didn’t know! There are so many facets of the power industry: generation, protection and controls, distribution and delivery, reliability, drives, uninterruptable power supplies, system studies, safety, maintenance, testing, as well as other areas that are vital for the safe and reliable delivery and …
Performing offline electrical tests on transformers can be time consuming, especially when field measurements are not captured correctly the first time. This article identifies the electrical transformer test that technicians often struggle to perform efficiently and correctly and offers three field testing tips to address the issue. Building awareness can help test equipment users avoid situations where a significant amount …
Diagnosing the condition of complex systems such as high-voltage rotating machines has never been a simple task. Design requirements, the use of different materials, and demanding operating conditions require multiple off-line tests and on-line monitors to provide information on the machine’s condition. Part 1 of this article described the application of various off-line test techniques to assess stator and rotor …
When it comes to electrical systems in industrial and commercial facilities and power plants, total system reliability is the top priority. An approach to electrical system service that encompasses both ac and dc power systems is required. AC and dc systems play an interconnected and equally critical role in ensuring overall reliability, and daily production and equipment protection require seamless …
Diagnosing the condition of complex systems such as high-voltage rotating machines has never been a simple task. Design requirements, the use of different materials, and demanding operating conditions require multiple off-line tests and on-line monitors to provide information on the machine’s condition. Some tests only yield simple measurement results without high diagnostic value. This article describes the application of various …
Power factor measurement has long been accepted as an invaluable tool for identifying insulation defects such as aging, deterioration, moisture ingress, and localized failures involving the winding and bushing insulation of a power transformer. Historically, power factor measurements have been performed at a single test frequency (typically 60Hz) and at a single test voltage (typically 10kV). However, modern test instruments …
Electrical arc phenomena have been studied for a long time. It is an inevitable process that occurs during interruption of high electrical currents (e.g., during a short circuit current interruption). The effects of the electrical arc on the circuit breaker contacts are known, and great attention has been paid to developing methods to analyze arc behavior and minimize damage to …
Most people are all too aware of the effects humidity can have on human comfort and health, especially when combined with high temperatures. Perhaps less well known is how humidity can impact electrical systems. For example, high humidity can cause droplets of water to condense on circuits, producing problems such as shorting and corrosion. Many geographic regions are prone to …