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

Hey everyone! I’m Felix, a 10-year veteran in the power system industry. Today, we’re going to dive into an important topic — what are the common failures of Air Insulated Switchgear (AIS) voltage transformers? How do you identify these issues, and how can they be resolved? Let’s get started!1. Insulation DamageThe Problem You Might Encounter：One of the most frequent issues is insulation damage. This typically happens due to aging insulation materials, ove

Hey everyone, I’m Echo, and I’ve been working with voltage transformers (VTs) for 12 years.From tagging along with my mentor doing insulation tests to now leading teams handling all kinds of high-voltage equipment issues — I’ve done a lot of oil refilling in my time. Especially when it comes to 110 kV voltage transformers, oil refill is a key part of daily maintenance. But let’s be honest — it's also one of the biggest time-wasters.A fe

1. IntroductionOutdoor voltage transformers are key equipment for ensuring the safety of electrical apparatus. Scientific and comprehensive test analysis is required to avoid hazards and property losses caused by improper operation. Test analysis can guide the formulation of operation strategies and precautions, ensure the stable operation of equipment, and maximize economic and social benefits.2. Concept of Outdoor Voltage TransformersAn outdoor voltage transformer is essentially an outdoor ste

1. IntroductionFrequent occurrences of PT burnout and primary - side fuse melting in combined transformers lead to inaccurate energy meter measurement and seriously threaten the safe operation of the power grid. This paper focuses on the repeated PT damage and fuse melting issues of a 35 kV combined transformer, investigates the fault causes, proposes solutions, and recovers the incorrect electricity quantity through correction coefficients. This effectively reduces grid losses and mitigates ser

Voltage transformers (PTs) consist of iron cores and winding coils, working similarly to transformers but with small capacity. They convert high voltage to low voltage for protection, measurement and metering devices, widely used in plants/stations. Classified by insulation: dry - type (≤6 kV), cast - type (indoor 3 - 35 kV), oil - immersed (outdoor ≥35 kV), and SF₆ gas - filled (for combined appliances).During substation operation, accidents from PT electromagnetic resonance or in

Hey everyone, I’m Echo, and I’ve been working with voltage transformers (VTs) for 12 years.From learning how to wire and do error tests under my mentor’s watchful eye, to now participating in all kinds of smart substation projects — I’ve seen the power industry evolve from traditional systems to fully digital ones. Especially in recent years, more and more 220 kV GIS systems are adopting electronic voltage transformers (EVTs), slowly replacing th

In power systems, voltage transformers in GIS (Gas Insulated Switchgear) play a crucial role in voltage measurement and relay protection. Selecting the right model and installing it correctly is vital for the stable operation of the equipment. The following points should be noted regarding selection and installation.I. Key Points for Selection(1) Matching Rated Parameters Voltage Level: It must be consistent with the voltage level of the GIS system. For example, 110kV and 220kV GIS systems requi

1. Causes of ResonanceA 500kV GIS switching station is designed following the principle of “primary equipment intelligence and secondary equipment networking”. The PT high - voltage side has no disconnector and is directly connected to the bus GIS. Through the analysis of fault recording diagrams, when the 5021 circuit breaker opens, the fracture capacitance and PT form a series circuit. Moreover, the bus voltage, after being paralleled by the PT inductance, shows inductive c

Automatic backup switching (ABTS) devices are core components ensuring the safe, reliable, and stable operation of factory power grids. Their startup logic strictly follows the dual criteria of "loss of voltage in the working power supply + no - current detection", effectively avoiding misjudgments caused by secondary disconnection of voltage transformers (VTs) or maloperations of ABTS due to secondary circuit faults of current transformers (CTs). The activation condition requires both "no volta

By Echo, 12 Years in the Electrical IndustryHi everyone, I'm Echo, and I've been working in the electrical industry for 12 years.From early involvement in commissioning and maintenance of distribution rooms to later participation in electrical system design and equipment selection for large-scale projects, I’ve witnessed how voltage transformers have evolved — from traditional analog devices to intelligent, digital components.The other day, a new colleague from a power compan