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 ParametersVoltage Level: It must be consistent with the voltage level of the GIS system. For example, 110kV and 220kV GIS systems requir

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

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 you perform an

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.Within

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 character

Hi everyone, I'm James, and I've been working with current transformers (CTs) for 10 years. Today, I’ll talk about what you need to watch out for when selecting and installing GIS current transformers.Part 1: Key Considerations During Selection1. Accuracy ClassProtection-grade CTs: Used for relay protection — focus on overload capacity and transient response.Metering-grade CTs: Used for billing purposes — require high accuracy, usually 0.2S or 0.5S class.2. Rated Primary Curren