Views: 0 Author: Luna Publish Time: 2026-09-08 Origin: Zhejiang Shengxian Electric Technology Co., Ltd
In 10kV distribution systems, metal-clad withdrawable switchgear is the undisputed workhorse. But when a project requires higher capacity — such as wind farms, solar substations, or 35kV distribution systems in large industrial plants — a higher voltage class is needed: 40.5kV metal-clad withdrawable switchgear.
It looks similar in construction to 12kV switchgear, but there are significant differences in voltage rating, insulation requirements, cabinet dimensions, and application scenarios.
This article covers the basic features of 40.5kV switchgear, its key differences from 12kV switchgear, and where it is typically used.
40.5kV metal-clad withdrawable switchgear is an indoor medium voltage metal-enclosed switchgear used in 40.5kV, 50Hz three-phase AC power systems for receiving, distributing, controlling, and protecting electrical energy.
Key features:
Metal-clad: Fully enclosed in a metal enclosure with grounded metal partitions between compartments
Withdrawable: The circuit breaker is mounted on a removable trolley that can be rolled out for maintenance
Indoor use: Designed for indoor installation
Compliant with IEC 62271-200
Typical applications for 40.5kV switchgear include:
Step-up substations for wind farms and solar PV plants (35kV side)
Generator outlets for small to medium generators
35kV distribution systems in industrial and mining facilities
35kV incoming/outgoing in substations
The two switchgear types look similar in appearance and structure, but differ in several critical aspects:
Feature | 12kV Switchgear | 40.5kV Switchgear |
|---|---|---|
Rated voltage | 12kV | 40.5kV |
Insulation clearance | Smaller | Larger (determined by voltage level) |
Cabinet dimensions | Relatively compact | Wider and taller |
Insulation component requirements | Standard | Higher (requires special design) |
Main application | 10kV distribution systems | 35kV distribution systems |
Typical projects | Factories, commercial buildings, residential complexes | Wind farms, solar step-up stations, large industrial plants |
The core difference is that the higher voltage level dictates higher insulation requirements. 40.5kV demands greater insulation clearances, longer creepage distances, and larger electrical gaps for insulation components — resulting in a larger cabinet size and specially designed insulation parts.
The cabinet structure of 40.5kV switchgear is similar to 12kV, featuring a metal-clad design with internal metal partitions dividing the cabinet into several independent compartments:
Compartment | Location | Key Components |
|---|---|---|
Circuit Breaker Compartment | Middle-front | Circuit breaker on withdrawable trolley |
Busbar Compartment | Rear-upper | Main busbars, branch busbars |
Cable Compartment | Rear-lower | Cable connections, current transformers, surge arresters |
Instrument Compartment | Front-upper | Protection relays, meters, control panel |
The breaker trolley also has three distinct positions: Service Position, Test/Isolation Position, and Withdrawn Position. PT trolleys and isolation trolleys are also common configuration units.
Due to the higher voltage level, the insulation components (such as wall bushings and contact boxes) in 40.5kV switchgear require special design — shielding is typically incorporated to improve insulation service life.
Scenario 1: Step-up Substations for Wind Farms and Solar PV Plants
Wind and solar projects typically step up voltage from low voltage (e.g., 690V) to 35kV before connecting to the grid. 40.5kV switchgear is the core equipment for 35kV side distribution and protection.
Scenario 2: Small to Medium Generator Outlets
Some small to medium generator sets (such as hydroelectric or diesel plants) have an outlet voltage of 35kV, requiring 40.5kV switchgear for generator outlet protection.
Scenario 3: 35kV Distribution Systems in Industrial Plants
Large factories (steel, cement, chemical) with 35kV incoming supply typically use 40.5kV switchgear for main incoming and distribution.
When purchasing 40.5kV switchgear, the following parameters should be defined:
Item | Notes |
|---|---|
Rated voltage | 40.5kV |
Rated current | Select based on load (typically 630A–3150A) |
Short-circuit breaking capacity | Must exceed the system‘s prospective short-circuit current |
Breaker type | Vacuum circuit breaker or SF6 circuit breaker |
Insulation component requirements | Confirm design and shielding scheme for wall bushings and contact boxes |
Cable entry/exit | Cable incoming/outgoing or overhead line options |
Anti-condensation measures | 35kV insulation components (especially contact boxes) are prone to condensation — heating and ventilation should be considered |
40.5kV metal-clad withdrawable switchgear is the core equipment for 35kV distribution systems.
If you are planning a 35kV project — wind farm, solar plant, large factory, or substation — this is a solution worth serious consideration.
For project-specific selection advice, feel free to contact us.
Contact us:
Web: https://yqsxdl.en.made-in-china.com/
WhatsApp: +195 1818 9858
Mail: lunahe927@gmail.com
