Free Expert Guides on Power Systems, Circuit Design & Electrical Troubleshooting

Hey everyone, I'm Oliver, and I've been working with current transformers (CTs) and voltage transformers (VTs) for 8 years.From assisting my mentor on site to leading high-voltage testing teams and conducting error calibrations independently, I’ve dealt with all kinds of instrument transformers — especially those used in GIS systems. The error test for voltage transformers is something I perform regularly.A few days ago, a friend asked me: “Oliver, how exactly do yo

In UHV GIS, current transformers are key to electric energy metering. Their accuracy determines power trade settlements, so on - site error verification perJJG1021 - 2007is needed. On - site, use power supplies, voltage regulators, and current boosters. Due to encapsulation in GIS, build test circuits via exposed grounding knives, bushings, and return conductors; right circuits simplify wiring and boost accuracy.Challenges like large test current, long circuits, and high impedance exist, but rea

I’m Oliver, an 8 - year current transformer testing pro. Today, let’s break down new and old polarity test methods for GIS current transformers—how they work and their pros/cons.1.Testing Methods1.1New Method Pre - test ops: Open FDS21/FDS22 fast disconnectors + DS23 disconnector. Close CB21 breaker, then ES21/ES22 grounding disconnectors. Disconnect ES21’s SF6 - shell ground. Wiring: Connect battery between ES21’s moving contact (negative ground

Fellow electric power calibration workers, you must have encountered this situation: The nameplate of an outdoor current transformer has been tormented by wind, sun, rain, and freezing, to the point where the transformation ratio is indistinguishable! Don't panic, we have a solution - use a current transformer calibrator and through the “transformation ratio trial calibration method”, we can figure out the actual transformation ratio and errors clearly. Here, taking the SHGQ

By Oliver, 8 Years in the Electrical IndustryHi everyone, I'm Oliver, and I've been working in the electrical industry for 8 years.From early days doing substation equipment commissioning to now managing protection and metering configurations for entire distribution systems, one of the most frequently used devices in my work has been the Current Transformer (CT).Recently, a friend who's just starting out asked me: “How do you test current transformers? Is there a simple and effective w

With the development of modern economy and science and technology, photoelectric current transformers (PECTs) have fully transitioned from the trial operation stage to practical application. As a front - line testing personnel, I deeply feel their importance in the power system during daily work. I also realize the necessity of conducting in - depth research on their testing systems and calibration methods. This not only promotes the engineering application of PECTs but also enables the accurate

Practical Experience Sharing from an Electrical Engineer in the FieldBy Oliver, 8 Years in the Electrical IndustryHi everyone, I'm Oliver, and I've been working in the electrical industry for 8 years.From early involvement in substation commissioning and equipment inspection, to now managing the maintenance and fault analysis of entire power systems, one of the most frequently encountered devices in my work has been the voltage transformer (VT / PT).Recently, a friend who's just starting out ask

1 Pre - commissioning InspectionAs a front - line tester, before formally commissioning a dry - type transformer, I need to carry out a comprehensive and systematic inspection. First, I conduct a visual inspection of the transformer body and its accessories, carefully checking for mechanical damage or deformation. Then, I check whether the leads of the high - and low - voltage windings are firmly connected and whether the bolt tightening torque meets the standard requirements (usually 40 - 60N&a

In recent years, as distribution automation advances, load switches see wider use in distribution lines. Yet, mechanical - failure - induced accidents are on the rise, burdening line operation and maintenance.Poor mechanical performance is the main cause of switch faults. Many scholars study large - scale switchgear operation, using methods like coil current detection, vibration signal analysis, switch travel testing, ultrasonic flaw detection, and infrared thermometry. Motor - current - based s

As a technician with years of on-site experience in power testing, I understand the importance and complexity of load switch testing. Below, I combine practical work experience to elaborate on the full process of load switch testing, from testing items and methods to equipment and procedural specifications.I. Routine Electrical Performance Testing(1) Loop Resistance TestLoop resistance is a core indicator for evaluating a load switch's conductivity. I strictly follow GB/T 3804 and GB 1984 standa