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

1. Accident Overview1.1 Structure and Connection of 35kV GIS Switchgear Voltage TransformerThe ZX2 gas-insulated double-bus switchgear, manufactured in March 2011 and officially put into operation in July 2012, is configured with two groups of bus voltage transformers (PTs) for each bus section. The two PT groups of the same bus section are designed in one switchgear cabinet with a width of 600 mm. The three-phase PTs are arranged in a triangular formation at the bottom of the cabinet.The PTs ar

1. Accident OverviewA newly - built 110kV substation’s GIS exploded during commissioning due to a PT secondary circuit short - circuit. Though the cause was simple, consequences were severe, warranting reflection.2. Accident ProcessOn the power - transmission day: The upper - level power supply charged the 110kV GIS (a combined appliance). 20s after closing the incoming switch and first live - impacting the 110kV bus, white smoke emerged between the PT compartment and control cabinet.

I'm Oliver, with 8 years of experience in current transformer testing. These are all practical experiences, shared with you1 Maintenance of Current TransformersHaving been in the business of current transformer testing for 8 years, I know a thing or two about their maintenance! The maintenance of current transformers is divided into minor repairs, intermediate repairs, and major overhauls.Minor repairs mainly involve opening the cover (if necessary) and changing the oil, usually carried out once

Gas - insulated switchgear (GIS) , often called “SF6 combined electrical apparatus”, is widely used in power systems for its high reliability, small footprint, low noise, and low loss. It encloses high - voltage devices like circuit breakers, fast grounding switches, current transformers, and busbars in a grounded metal shell filled withSF6gas. Each device sits in a separate gas chamber with different pressures. The CT terminal block divides gas chambers, connects components,

I'm Felix, a 15-Year Veteran in the CT Industry, Sharing What You Need to Watch Out ForHi everyone, I'm Felix, and I've been working with current transformers (CTs) for over 15 years. Today, let’s talk about why the secondary insulation of outdoor CTs sometimes drops, and what you can do to prevent it.Common Causes:1. Moisture Ingress — Poor Sealing is the Biggest Problem!Outdoor CTs are constantly exposed to wind and rain. If the sealing isn't tight enough, moisture can get

As a front - line fault maintenance worker, I deal with current transformers (CTs) daily. A CT’s secondary winding in operation must never open - circuit! Once open - circuited, the secondary current and demagnetizing potential vanish. All primary - side magnetic potential then becomes the iron core’s exciting potential, sharply increasing its magnetic flux density. High voltage on the secondary side will endanger safety anytime.Despite strict power operation regulations, use

As a front - line maintenance technician, I deal with current transformers (CTs) daily. CTs convert high - magnitude primary current to low - magnitude secondary current for substation/line protection and measurement, operating in series long - term. However, they face faults from external (unbalanced loads, wrong wiring, etc.) and internal (insulation defects) issues. These faults, like secondary open - circuits or insulation breakdown, harm measurement accuracy, protection operation, and grid

1. Fault SituationIn September 2023, as a front - line fault maintenance worker, I detected abnormal voltage on the 10kV Section I bus of a substation during monitoring duty and informed the operation and maintenance team. The monitoring system showed: U0 = 0 kV, Ua = 6.06 kV, Ub = 5.93 kV, Uc = 6.05 kV, Uab = 10.05 kV, Ubc = 5.94 kVMy team and I rushed to the site. We suspected the secondary air circuit breaker of the 10kV Section I bus voltage transformer was closed and found the U - phase fus

By Felix, 15 Years in the Electrical IndustryHi everyone, I'm Felix, and I've been working in the electrical industry for 15 years.From early involvement in traditional substation commissioning and maintenance to now managing electrical system operations for multiple photovoltaic and wind power projects, one of the most frequently encountered devices I deal with is the Electromagnetic Voltage Transformer (PT).The other day, a shift operator at a new energy plant asked me: “We have an e

Hi everyone, I’m Felix, and I’ve been working in electrical equipment fault repair for 15 years.Over these years, I’ve traveled across factories, substations, and distribution rooms all over the country, troubleshooting and repairing all kinds of electrical equipment. Dry-type transformers are among the most common devices we deal with.Today, a friend asked me: “What does it mean when the low-voltage side of a dry-type transformer has low insulation resist