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

Hey everyone, I'm James, and I've been working with current transformers (CTs) for 10 years.From running around job sites with my mentor, wiring and debugging equipment, to now leading substation projects and handling all kinds of complex CT issues — I’ve worked with a lot of outdoor current transformers over the years. And trust me, I’ve made mistakes, learned from them, and picked up some real-world experience along the way.A few days ago, a fellow engineer asked

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

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 Class Protection-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

Practical Experience Sharing from an Electrical Engineer in the FieldBy James, 10 Years in the Electrical IndustryHi everyone, I'm James, and I've been working in the electrical industry for 10 years.From early involvement in substation design and equipment selection, to later taking charge of relay protection and automation system commissioning for entire projects, one of the most frequently used devices in my work has been the current transformer (CT).Recently, a friend who's just starting out

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 James, 10 Years of Electrical Equipment Maintenance ExperienceHi everyone, I’m James, and I’ve been working in electrical equipment fault repair for 10 years.Over the past decade, I’ve worked in factories, substations, and distribution rooms of all sizes, involved in the installation, commissioning, maintenance, and troubleshooting of dry-type transformers. Dry-type transformers are among the most common electrical devices we deal with on a daily basis.Today, a n

1 Pre - installation PreparationAs a front - line installer, I know very well that the preparation work before installing a dry - type transformer must be thorough. First, I will carefully review the design drawings and technical documents, and check one by one the technical parameters such as the model specification, rated capacity, and voltage level of the transformer to ensure they are in full compliance with the design requirements. Then, I will conduct an unpacking inspection of the transfo

As a frontline operator who deals with smart electricity meters daily, I’m well - versed in the design and operational norms of load switches (both internal and external) in these meters. Below, I’ll break down the technical requirements and practical key points based on my on - site experience for easy reference.I. Basic Understanding of Internal and External Load SwitchesIn the type specifications for single - phase and three - phase smart electricity meters (such as enviro

Sizing Principles and Technical Parameters of Photovoltaic TransformersSizing photovoltaic transformers requires a comprehensive consideration of multiple factors, includingcapacity matching, voltage ratio selection, short - circuit impedance setting, insulation class determination, and thermal design optimization. The key sizing principles are as follows:(I) Capacity Matching: Fundamental for Load BearingCapacity matching is thecore prerequisitein sizing photovoltaic transformers. It requires a