High Voltage Switchgear

What is the High Voltage Switchgear？

High voltage switchgear is employed to safely start, stop, and protect high-voltage electrical systems (typically exceeding 36kV), facilitating the smooth progression of processes such as power generation, distribution, transmission, and isolation. It incorporates various components, including circuit breakers, transformers, isolators, and relays, to manage and safeguard your electrical system during both operational and fault conditions.

High Voltage Switchgear Function​

Ensuring the Operation of High Voltage Currents

High-voltage switchgear is capable of withstanding, switching on and off, and controlling high-voltage electricity, thereby facilitating the smooth transmission and distribution of high-voltage power. It can also be promptly disconnected when necessary, thus guaranteeing the stability and high efficiency of the power system.

Fault Monitoring and Response

The transformers, instrument transformers and other components within the high-voltage switchgear can continuously monitor the status of high-voltage currents and provide you with reports. Upon detecting anomalies, it can promptly issue early warning signals to protective components within the equipment, such as relays and circuit breakers. This enables them to respond swiftly, preventing risks from materialising and causing harm.

Minimise Downtime

Upon detecting anomalies, high-voltage switchgear employs insulating media to isolate faulty equipment and interrupt current flow. This not only prevents threats to the entire system but also permits the continued operation of other equipment, delivering a more reliable power system.

Ensuring Safety During Maintenance Operations

The circuit breakers and earthing switches within high-voltage switchgear, along with the associated network, can completely isolate faulty equipment from the current supply while providing you with a clearly observable status. This significantly enhances electrical and personnel safety during repair and maintenance procedures.

High Voltage Switchgear Components​

Circuit Breaker

Circuit breakers serve as user-protected components within high-voltage switchgear, safeguarding the power system. During operation, they continuously monitor operational status signals. Should a circuit fault occur(such as a short circuit or overload), the circuit breaker responds within milliseconds to interrupt the current flow. You can reset circuit breakers and re-engage multiple times. This not only ensures circuit safety but also extends the operational lifespan of the high-voltage switchgear.

Isolator

An isolator, also known as a disconnect switch, is used to control the activation and deactivation of circuits. It enables complete disconnection of equipment from the circuit, making it commonly employed during maintenance to clearly indicate the current circuit status and ensure operational safety throughout the process.

Current Transformers

Current transformers are employed to measure and continuously monitor current conditions, transmitting signals to other protective devices. They promptly detect abnormal situations and issue warning signals, working in tandem with protective equipment to maintain circuit safety.

Potential Transformer

As monitoring equipment requires lower voltages, potential transformers are employed to modify voltage levels. These devices reduce voltage before electricity passes through low-voltage apparatus, thereby ensuring the monitoring process proceeds smoothly. This not only safeguards equipment performance and safety but also extends the operational lifespan of the apparatus.

Protection Relay

The protection relay continuously monitors the current and voltage conditions within high-voltage switchgear. Upon detecting a fault, it immediately transmits signals to components such as circuit breakers. By coordinating with circuit breakers, it rapidly interrupts current flow, enabling an efficient response.

Busbars

Busbars serve to connect various equipment. Within high-voltage switchgear, busbars are responsible for current distribution, playing a crucial role in the power supply process to ensure the stable operation of your equipment.

Earthing Switch and Grid

Earthing grids are typically buried underground. When a circuit is closed, it conducts residual currents from the power system into the earth, thereby preventing such residual currents from posing a serious safety risk.

Control Panel and Indicators

The control panel and indicators within the motor control centre convey circuit status, enabling easier setup and monitoring to significantly enhance maintenance efficiency. Typically featuring a simple and clear design, they support automatic adjustment and remote control, simplifying operational procedures and facilitating more convenient maintenance.

Types of High Voltage Switchgear ​

Depending on the type of insulating medium employed, high-voltage switchgear primarily comprises air insulated, gas insulated, vacuum insulated, oil insulated, and solid insulated switchgear.

Air Insulated Switchgear

Air insulated switchgear utilises ambient air as its insulating medium. Consequently, its design is relatively bulky, and optimal performance requires installation in an open, well-ventilated environment. The use of air reduces the initial cost of your high voltage switchgear, but also renders its performance susceptible to atmospheric factors such as humidity.

Gas Insulated Switchgear

Sulphur hexafluoride gas is the commonly used insulating medium in gas-insulated switchgear. Compared to air insulated switchgear, It is unaffected by external circumstances, thus offering higher reliability and superior insulating properties. However, you will also incur higher initial and maintenance costs.

Vacuum Insulated Switchgear

Vacuum insulated switchgear utilises vacuum circuit breakers. Benefiting from the vacuum’s high dielectric strength and exceptional reliability, it delivers outstanding performance in high voltage applications. Moreover, you may utilise it in indoor projects where space is limited.

Oil Insulated Switchgear

Insulating oil (such as mineral oil) may also serve as the insulating medium for high voltage switchgear, offering excellent operational performance. However, owing to the environmental concerns and fire risks, you must verify suitability for application in accordance with local regulations and anticipate increased maintenance requirements.

Solid Insulated Switchgear

Solid insulated switchgear employs solid materials such as highly insulating epoxy resin to replace air in circuit interruption. This high voltage switchgear does not release toxic substances. If environmental considerations are your foremost priority, it represents an excellent choice.

Hybrid Insulated Switchgear

Hybrid insulated switchgear is a type of high-voltage switchgear that employs a combination of air and gas for insulation. It combines the advantages of both air-insulated and gas-insulated switchgear, minimising environmental impact on performance while offering you lower costs and less space. 

Applications of High Voltage Switchgear

Large Residential Estates

You can apply high voltage switchgear within large, densely populated residential estates to ensure the reliable operation of residents’ electrical installations. Its predictive warning and response capabilities enhance power stability across the estate. This can elevate residential satisfaction while preventing significant losses arising from operational failures.

Industrial

High voltage switchgear serves as the ideal management equipment for various high-voltage power generation and transmission applications within industrial sectors such as mining, manufacturing, and chemical processing. The large-scale mechanical and electrical installations within these industries require high-voltage switchgear capable of withstanding substantial electrical loads to ensure a sustained, stable power supply and safe disconnection.

Commercial

Benefiting from the robust power management capabilities, operational stability and safety of high-voltage switchgear, it is well-suited for use in various commercial settings such as hospitals, schools, large shopping centres, offices and data centres. It delivers continuous operation, minimises fault occurrence and thereby enhances operational efficiency.

If you are seeking suitable switchgear for large-scale and high-load power systems, high voltage switchgear can provide stable and secure electrical control. Zhongshao offer high quality and customised high-voltage switchgear solutions. Please feel free to enquire at any time.