A) Medium Voltage (MV) Switchgear
1. Function
Medium voltage switchgear plays a crucial role in an electrical system by controlling the flow of electricity. It is designed to safely make, carry, and break current under both normal and fault conditions. By isolating healthy sections of the system from faulty ones, it protects both people and property from potential hazards.
2. Types of Switchgear
Switchgear can be classified based on several factors:
- Isolators
- Switch Fuse Units (SFUs)
- Circuit Breakers
These types can be further broken down by:
- Installation:
- Mechanism:
- Technology:
- Air Insulated Switchgear (AIS)
- Gas Insulated Switchgear (GIS)
- Application:
3. Components
The key components of MV switchgear include:
- Isolators/Switch Fuse Units/Circuit Breakers: These devices interrupt the flow of current under normal or abnormal conditions. They can operate automatically (except for SFUs) or manually.
- Busbars: These conductors distribute power within the switchgear. They are typically made from copper or aluminum, depending on the current and application requirements.
- Instrument Transformers: These include Current Transformers (CTs) and Voltage (Potential) Transformers (VTs) that monitor electrical parameters for protection and system monitoring. We’ll dive deeper into instrument transformers in a future article.
4. Location
Switchgear is typically located in the primary panel of the electrical system.
5. Role
Switchgear serves to isolate faulty sections of the system, ensuring that healthy sections can continue functioning. It also allows for safe maintenance work and protects both personnel and equipment from abnormal conditions.
B) Protection Relay
1. Function
Protection relays are intelligent devices that continuously monitor electrical parameters such as current, voltage, and frequency. When an abnormal condition is detected, these relays trigger actions like tripping a circuit breaker, preventing damage to the system and ensuring personnel safety.
2. Types of Protective Relays
- Overcurrent Relays: These trip the circuit breaker when the current exceeds a preset level.
- Voltage Relays: These activate when there are overvoltage or undervoltage conditions.
- Differential Relays: These compare the current entering and leaving a protected area to identify faults.
- Distance Relays: These operate based on impedance to detect faults in a line section.
Relays can also be classified by:
- Type: Electromechanical, Numerical, Digital
- Communication: Non-communicable, Communicable
- Communication Protocols: Different relays support various communication methods, enhancing system integration.
Further details on relay types will be covered in a future article.
3. Components
Protection relays include several essential components:
- Current and Voltage Sensors (CTs and VTs): These sensors measure electrical parameters.
- Processing Units: Analyze data and initiate protective actions.
- Communication Interfaces: Facilitate the transfer of data and trip signals to the switchgear.
4. Location
Relays are typically located in the Low Voltage Compartment (LVC).
5. Role
Protection relays act as the "brain" of the system, detecting faults and instructing the switchgear to take corrective action. They provide vital intelligence and automation to minimize damage and enhance system reliability.
Conclusion
- Medium Voltage Switchgear: This is the physical hardware responsible for controlling and protecting medium voltage circuits. It includes devices like circuit breakers and isolators to manage power distribution and ensure safety.
- Protection Relay: These devices add intelligence to the system by continuously monitoring electrical parameters and triggering protective actions when faults occur. They complement switchgear by automating fault detection and system protection.
Together, switchgear and protection relays work in tandem: switchgear handles the physical control and interruption of power flow, while protection relays monitor system conditions and instruct the switchgear to act when necessary.
At Nuventura, we offer the SF6-free nu1 switchgear panel, utilizing dry air insulation. Our flexible switchgear configurations are designed to meet various customer needs, such as circuit breaker feeder panels, disconnector panels, bus bar sectionalizer panels, bus riser panels, and bus bar earthing panels.
Our Low Voltage Compartment (LVC) is adaptable to accommodate relays of any make and model, ensuring smooth integration. Plus, with our draw-out design and Harting plugs, installation and on-site LVC exchanges are quick and efficient.
Professiona Switchgear supplier and manufacturer
- Zhejiang GONGSHUN Electrical Co.,Ltd (electricgs.com), Our company was founded in the late 1990s, specializing in the production of inflatable cabinets, SF6 inflatable cabinets, and various high and low voltage complete sets of electrical equipment. It has multiple subsidiaries under its jurisdiction, including high-voltage load switch branch, high-voltage circuit breaker branch, high-voltage fuse branch, and technology development branch.Our technical expertise, comprehensive product portfolio and long-term rich experience are helping many customers in need to solve their power problems. We’re happy to help at any time. Whether you need application product advice or technical assistance, our global service team is committed to providing you with the right support. For more technical information about medium voltage earthing switch, feel free to contact us, send an email to gongshun@electric-cn.com
- Our company specializes in producing 12KV-40.5KV series high-voltage electrical products: FZN58, FLN48, FLN36, FZRN25, FZN21, FN18, ZFN16, FN12, FN8, FN7, FN5, XRNT, XRNP, VS1, ZN28, ZW8, ZW32, JN15, GN19, GN22, GN24, GN30, CLXGN15-12, HXGN □ -12, DXG-12 (L), DFW □ -12 high-voltage cable branch box, CLXGN □ -12 (SF6) series inflatable cabinet 12KV and 35KV cable accessories, etc; CLVXP-12 indoor AC high voltage fixed switchgear, CL-SIS-12 compact solid insulated ring main unit, professional assembly Schneider SC6 (SF6) series load switchgear, ABB produced SFG (SF6) series load switchgear and other series products; Distribution and agency of high-voltage load switches and inflatable cabinets produced by Schneider Electric and ABB; Siemens produces the 3AJ1 series of indoor medium voltage vacuum circuit breakers and other related products. The company has a complete range of products and has been operating safely on domestic and international power grids for a long time, receiving unanimous praise from both new and old users. Among them, multiple products such as FZRN25, FN12, FLN36-12, XRNT-12 have been exported to various countries and regions in East Asia, South Asia, Southeast Asia, Africa, and the United States.
