3KV 6KV 10KV Medium Voltage Switchgear

The 3kV 6kV 10kV Medium Voltage Switchgear is designed for medium-voltage power distribution, control, protection, and isolation. The technical configuration can be customized according to the system voltage, short-circuit level, load characteristics, installation environment, and project requirements.

1. Rated Voltage

The switchgear can be configured for different medium-voltage systems, including:

• 3kV

• 3.3kV

• 6kV

• 6.6kV

• 10kV

• 10.5kV

The actual rated voltage should be selected according to the system's operating voltage and the required equipment insulation level.

2. Rated Current

The rated current can be customized according to the connected load and power distribution requirements.

Common configurations include:

• 630A

• 1250A

• 1600A

• 2000A

• 2500A

• 3150A

Higher current configurations can be engineered where required.

3. Vacuum Circuit Breaker

The switchgear uses a vacuum circuit breaker (VCB) as the primary switching and protection device.

The VCB provides:

• Reliable switching

• Short-circuit interruption

• Long electrical service life

• Low maintenance requirements

• Fast fault clearing

Withdrawable VCB configurations are particularly suitable for industrial applications requiring convenient inspection and maintenance.

4. Short-Circuit Withstand

The short-circuit withstand rating is selected according to the calculated fault current of the electrical system.

The final design can consider:

• Rated short-time withstand current

• Rated peak withstand current

• Short-circuit duration

• Circuit breaker breaking capacity

• Busbar mechanical strength

Typical values may include 20kA, 25kA, 31.5kA, 40kA, or other project-specific ratings.

5. Busbar Configuration

The switchgear can be designed with:

Single Busbar

Suitable for standard power distribution applications.

Sectionalized Busbar

Allows the switchboard to be divided into sections and can improve operational flexibility.

Double Busbar

Available for applications requiring greater operational flexibility and redundancy.

6. Protection & Control

The protection system can integrate numerical protection relays for functions such as:

• Overcurrent Protection

• Short-Circuit Protection

• Earth-Fault Protection

• Undervoltage Protection

• Overvoltage Protection

• Phase Failure Protection

• Motor Protection

• Transformer Protection

• Busbar Protection

Protection settings can be configured according to the project's protection coordination study.

7. Instrument Transformers

The switchgear can be equipped with:

Current Transformers (CT)

Used for:

• Protection

• Metering

• Measurement

• Energy monitoring

Voltage Transformers (VT/PT)

Used for:

• Voltage measurement

• Protection

• Metering

• Synchronization

• Power monitoring

CT and VT ratios, accuracy classes, and burden can be customized according to project requirements.

8. Earthing System

An integrated earthing switch can be provided for safe maintenance and isolation.

The grounding system can include:

• Earthing switch

• Grounding busbar

• Cable grounding connection

• Mechanical interlock

• Electrical interlock

The earthing switch can be mechanically interlocked with the circuit breaker and withdrawable unit to prevent unsafe operating sequences.

9. Interlocking System

The switchgear can incorporate comprehensive mechanical and electrical interlocking.

Typical functions include:

• Preventing circuit breaker closing when the earthing switch is closed

• Preventing earthing switch operation when the circuit breaker is closed

• Preventing withdrawal of the breaker under unsafe conditions

• Preventing access to energized compartments

• Preventing incorrect switching operations

10. Enclosure & Compartments

The metal-clad enclosure can be divided into independent functional compartments, typically including:

• Circuit breaker compartment

• Busbar compartment

• Cable compartment

• Low-voltage/control compartment

This compartmentalized structure helps isolate different electrical sections and facilitates inspection and maintenance.

11. Protection Degree

The standard enclosure can be designed for typical indoor medium-voltage applications.

Higher enclosure protection can be considered according to:

• Dust conditions

• Humidity

• Indoor environment

• Cable trench configuration

• Project requirements

12. Monitoring & Communication

For intelligent substations and industrial power systems, the switchgear can integrate:

• Multifunction power meters

• Temperature monitoring

• Breaker status monitoring

• Protection relay communication

• RS485

• Modbus RTU

• Ethernet

• SCADA integration

This enables centralized monitoring and management of the medium-voltage distribution system.

13. Installation Conditions

The standard configuration is intended for indoor installation.

The design can be customized according to:

• Ambient temperature

• Installation altitude

• Relative humidity

• Dust

• Corrosive atmosphere

• Seismic requirements

• Indoor ventilation

• Cable trench arrangement

For high-altitude or special environmental applications, appropriate insulation and equipment derating should be considered during engineering.

14. Applicable Standards

Depending on the specific switchgear type and project requirements, the equipment can be designed according to the applicable IEC 62271 series standards for high-voltage/medium-voltage switchgear and controlgear.

For example, IEC 62271-200 covers AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV.

The final applicable standard should be confirmed according to the selected switchgear design, destination market, and project specification.

15. Typical Electrical Configuration

A typical 10kV distribution system can be arranged as:

10kV Incoming Cable
↓
Vacuum Circuit Breaker
↓
CT / VT / Protection Relay
↓
Main Busbar
↓
Bus Coupler / Bus Section
↓
Outgoing VCB Feeders
↓
Transformer / Motor / Industrial Load

For EPC projects, the final technical parameters should be determined from the Single Line Diagram (SLD), load list, short-circuit calculation, protection coordination requirements, utility specifications, and applicable standards rather than selecting ratings solely from the nominal 3kV/6kV/10kV system voltage.

The 3kV 6kV 10kV Medium Voltage Switchgear can be customized according to the project's electrical system, load requirements, short-circuit level, protection philosophy, installation conditions, and applicable local or international standards.

1. Voltage Customization

The switchgear can be configured for different medium-voltage systems, including:

• 3kV

• 3.3kV

• 6kV

• 6.6kV

• 10kV

• 10.5kV

The rated voltage, insulation level, and related components are selected according to the actual system operating voltage.

2. Circuit Breaker Customization

The main switching device can be configured as a fixed or withdrawable vacuum circuit breaker.

Customers can specify:

• Rated current

• Breaking capacity

• Operating mechanism

• Control voltage

• Auxiliary contacts

• Trip/close coils

• Motorized operating mechanism

• Local/remote operation

Withdrawable VCBs are particularly suitable for industrial and EPC applications where maintenance flexibility is important.

3. Busbar Customization

The busbar arrangement can be designed according to the power distribution architecture.

Available configurations include:

Single Busbar
For conventional medium-voltage distribution.

Sectionalized Busbar
For systems requiring bus sectioning and operational flexibility.

Double Busbar
For applications requiring additional switching flexibility and redundancy.

Busbar current rating and short-circuit withstand capability are calculated according to the project electrical requirements.

4. Protection System Customization

The protection system can be configured according to the load type.

For transformer feeders, protection may include:

• Overcurrent

• Earth fault

• Transformer protection interface

• Temperature monitoring

For motor feeders:

• Overload

• Short circuit

• Earth fault

• Phase failure

• Motor-specific protection

For incoming feeders:

• Overcurrent

• Earth fault

• Undervoltage

• Overvoltage

• Other utility-specific functions

5. Instrument Transformer Customization

CT and VT/PT configurations can be selected according to the protection and metering requirements.

Customers can specify:

• Transformation ratio

• Accuracy class

• Protection class

• Number of cores

• Metering core

• Protection core

• Zero-sequence CT

• Special-purpose CT/VT requirements

6. Earthing & Interlocking Customization

The switchgear can be equipped with an integrated earthing switch and customized interlocking system.

Options include:

• Mechanical interlocking

• Electrical interlocking

• Breaker/earthing switch interlocking

• Door interlocking

• Key interlocking

• Motorized earthing switch

These features help prevent incorrect switching operations during maintenance.

7. Intelligent Monitoring

For modern industrial and substation applications, intelligent monitoring can be integrated into the switchgear.

Optional functions include:

• Real-time current monitoring

• Voltage monitoring

• Power monitoring

• Energy measurement

• Breaker status

• Temperature monitoring

• Partial discharge monitoring, where applicable

• Remote control

• Fault indication

Communication can be configured for integration with SCADA, PLC, EMS, or other supervisory systems.

8. Environmental Customization

The switchgear can be adapted for challenging installation environments.

Additional options may include:

• Space heaters

• Anti-condensation heaters

• Thermostats

• Enhanced ventilation

• Anti-corrosion coating

• Higher enclosure protection

• High-altitude design

• Dust protection

• Humidity protection

• Seismic reinforcement

Environmental parameters should be provided during the engineering stage to ensure appropriate equipment selection and derating.

9. Cabinet & Layout Customization

Cabinet dimensions and arrangement can be customized according to:

• Electrical components

• Cable size

• Cable entry direction

• Installation space

• Maintenance clearance

• Room layout

• Customer GA requirements

A complete lineup can be designed with:

Incoming Section + Metering Section + Bus Section + Bus Coupler + Outgoing Feeders

according to the project SLD.

10. EPC Project Customization

For EPC projects, the switchgear can be manufactured according to the customer's complete technical package, including:

• Single Line Diagram

• Load List

• Protection Coordination Study

• Technical Specification

• General Arrangement Drawing

• Wiring Diagram

• Equipment Schedule

• Component List

• ITP

• FAT Procedure

The manufacturer can provide customized engineering drawings for customer approval before production.

Recommended Information for Customization

To prepare an accurate technical proposal, customers are recommended to provide:

Rated Voltage + Rated Current + Frequency + Short-Circuit Level + SLD + Load List + Incoming/Outgoing Feeder List + Protection Requirements + Installation Conditions + Applicable Standard + Quantity + Destination Country.

For a 3kV/6kV/10kV medium-voltage switchgear project, the SLD and short-circuit level are especially important because they determine the appropriate circuit breaker, busbar rating, CT/VT configuration, protection system, and overall cabinet design.

The 3kV 6kV 10kV Medium Voltage Switchgear is carefully inspected, protected, and packed according to its cabinet dimensions, weight, electrical configuration, transportation method, and destination. For overseas and EPC projects, customized export packing can be provided to protect the equipment during loading, sea transportation, unloading, and long-term storage.

1. Pre-Shipment Inspection

Before packing, each switchgear lineup is inspected against the approved technical documents.

Inspection includes:

• Cabinet quantity and identification

• Cabinet dimensions

• Circuit breaker configuration

• Busbar arrangement

• Protection relay installation

• CT/VT installation

• Earthing switch

• Interlocking system

• Internal wiring

• Nameplates and labels

• Accessories and spare parts

• Factory test results

The final packing list is checked against the actual shipment before loading.

2. Circuit Breaker Protection

For withdrawable vacuum circuit breaker configurations, the breaker and moving components are secured during transportation.

Additional protection can be provided for:

• VCB operating mechanism

• Moving contacts

• Racking mechanism

• Auxiliary contacts

• Control wiring

• Breaker terminals

Withdrawable units and loose accessories can be packed separately where required.

3. Internal Electrical Protection

Sensitive electrical components are protected against impact, dust, vibration, and moisture.

Protection may include:

• Insulating protective materials

• Foam or shock-absorbing materials

• Protective film

• Plastic covers

• Moisture-proof materials

• Desiccants

• Securing of movable components

All cabinet doors and accessible compartments are secured before shipment.

4. Moisture Protection

For international sea transportation, moisture protection is particularly important.

The packing can include:

• Waterproof plastic film

• Moisture-proof inner wrapping

• Desiccant

• Sealed packaging

• Anti-condensation protection

This helps reduce the risk of moisture-related damage during long-distance transportation and temporary storage.

5. Export Wooden Packing

Depending on the shipment requirements, the switchgear can be packed using:

• Export wooden cases

• Reinforced wooden frames

• Pallets

• Shock-absorbing materials

• Waterproof outer covering

Heavy switchgear cabinets are reinforced to reduce movement and mechanical stress during transportation.

International wooden packaging can be prepared in accordance with applicable ISPM 15 requirements where required by the destination country.

6. Cabinet Separation

For large switchgear lineups, cabinets can be separated into individual shipping units according to:

• Cabinet dimensions

• Container dimensions

• Shipping weight

• Installation sequence

• Site handling conditions

Each package can be clearly identified with the corresponding cabinet number and project reference.

7. Packing Markings

Each package can be marked with important shipping information, including:

• Project name

• Customer name

• Cabinet number

• Package number

• Gross weight

• Net weight

• Dimensions

• Lifting position

• Center of gravity

• “Keep Dry”

• “This Side Up”

• “Handle With Care”

This helps the site team identify and handle each switchgear unit correctly.

8. Container Loading

Depending on the cabinet quantity and dimensions, shipments can be arranged using:

• 20ft containers

• 40ft containers

• 40HQ containers

• LCL shipments

• FCL shipments

The loading plan is developed according to cabinet dimensions and weight.

Heavy cabinets are positioned and secured appropriately to minimize movement during transportation.

9. Transportation Options

The switchgear can be transported using different logistics solutions:

Sea Freight
Recommended for complete switchgear lineups and large EPC projects.

Air Freight
Available for urgent spare parts, accessories, or small shipments.

Truck Transportation
Used for factory-to-port transportation or inland delivery.

Multimodal Transportation
Sea + truck or other combinations can be arranged according to the destination.

10. Loading & Securing

Before the container leaves the factory:

• Cabinet positions are checked

• Packages are secured

• Movement is minimized

• Heavy equipment is properly supported

• Lifting points are verified

• Container condition is inspected

• Packing photos are taken

For large projects, a container loading record can also be provided.

11. Shipping Documents

Depending on the contract and destination requirements, shipping documents can include:

• Commercial Invoice

• Packing List

• Bill of Lading

• Certificate of Origin

• Factory Test Report

• Routine Test Report

• Inspection Report

• Product Datasheet

• Operation & Maintenance Manual

• Installation Manual

• Certificate of Conformity

• Warranty Documents

• Project-specific documentation

12. EPC Project Packing

For EPC projects, packaging can be customized according to the customer's logistics and site installation requirements.

The manufacturer can arrange:

• Cabinet-by-cabinet identification

• Installation-sequence packing

• Customer-specific labels

• Separate accessory packing

• Spare-parts packing

• Detailed packing lists

• Container loading plans

• Shipping photos

This helps the EPC contractor identify the correct equipment quickly after delivery.

13. Storage After Delivery

If the switchgear needs to be stored before installation, the customer should keep the equipment in a clean, dry, well-ventilated environment and follow the manufacturer's storage instructions.

Particular attention should be paid to:

• Moisture

• Condensation

• Dust

• Water leakage

• High humidity

• Mechanical impact

The original protective packaging should remain intact until the equipment is ready for installation whenever practical.

14. Typical Packing Process

Factory Final Inspection
↓
Routine Testing Completed
↓
Circuit Breaker & Moving Parts Secured
↓
Internal Moisture Protection
↓
Protective Film / Waterproof Packaging
↓
Export Wooden Case or Reinforced Frame
↓
Package Marking & Identification
↓
Container Loading & Securing
↓
Shipping Documentation
↓
International Shipment

For 3kV, 6kV and 10kV medium-voltage switchgear, packing is particularly important because the equipment contains precision switching, protection, insulation, and control components. The final packing method should therefore be selected based on the cabinet configuration, transportation distance, climate, shipping method, and destination storage conditions.

The 3kV 6kV 10kV Medium Voltage Switchgear undergoes comprehensive manufacturer testing before shipment to verify its electrical performance, mechanical operation, insulation condition, protection functions, and overall assembly quality.

Testing is performed according to the approved technical specifications, drawings, factory procedures, and applicable IEC 62271 series requirements. Project-specific FAT (Factory Acceptance Test) can also be arranged for EPC projects.

1. Visual & Mechanical Inspection

The complete switchgear assembly is inspected against the approved drawings and technical documents.

Inspection includes:

• Cabinet dimensions

• Cabinet alignment

• Component installation

• Busbar arrangement

• Circuit breaker installation

• CT/VT installation

• Earthing switch

• Cable compartment

• Control compartment

• Nameplates

• Safety labels

• Surface coating

• Internal cleanliness

The actual configuration is checked against the approved Single Line Diagram (SLD), General Arrangement (GA) drawing, wiring diagram, and Bill of Materials.

2. Vacuum Circuit Breaker Test

The vacuum circuit breaker is inspected and functionally tested before shipment.

Testing may include:

• Circuit breaker ON/OFF operation

• Closing operation

• Opening operation

• Trip operation

• Manual operation

• Electrical operation

• Spring charging mechanism

• Auxiliary contacts

• Operating mechanism

• Breaker position indication

• Control circuit operation

For withdrawable VCBs, the following positions are also checked:

• Service position

• Test position

• Isolated position

• Withdrawal/insertion operation

3. Mechanical Interlocking Test

The interlocking system is tested to prevent incorrect operating sequences.

Typical checks include:

• Circuit breaker and earthing switch interlock

• Breaker closing interlock

• Earthing switch interlock

• Door interlock

• Withdrawable breaker interlock

• Position interlock

• Key interlock, if specified

The purpose is to ensure that unsafe operating conditions are prevented during normal operation and maintenance.

4. Protective Earthing Test

The protective earthing circuit is inspected to verify reliable electrical continuity.

The test covers:

• Main earth busbar

• Cabinet frame

• Doors

• Removable panels

• Cable compartments

• Circuit breaker compartments

• Earthing switch connections

All relevant exposed conductive parts must be properly connected to the protective earth system.

5. Insulation Resistance Test

Insulation resistance testing is performed on the relevant electrical circuits.

The test can be used to identify:

• Insulation deterioration

• Incorrect wiring

• Short circuits

• Moisture contamination

• Leakage paths

Testing can be performed between:

• Phase and phase

• Phase and earth

• Main circuit and control circuit

The test voltage and acceptance criteria are determined according to the applicable standard and project requirements.

6. Power-Frequency Withstand Test

A power-frequency dielectric withstand test is performed to verify the insulation capability of the completed switchgear assembly.

The test checks whether the insulation system can withstand the specified test voltage without:

• Insulation breakdown

• Flashover

• Abnormal discharge

• Excessive leakage

The test voltage is selected according to the equipment's rated insulation level and applicable IEC requirements.

7. Main Circuit Resistance Test

The resistance of the main conductive circuit can be measured to identify abnormal contact resistance or connection problems.

Inspection can cover:

• Circuit breaker contacts

• Busbar joints

• Cable connections

• Main circuit connections

• Disconnecting contacts

Abnormally high resistance may indicate poor contact, loose connections, contamination, or installation problems.

8. Circuit Breaker Timing Test

Where required by the project, the manufacturer can perform breaker operating-time measurements.

Testing may include:

• Closing time

• Opening time

• Trip time

• Phase synchronization

• Contact travel characteristics

This helps verify correct mechanical and electrical operation of the vacuum circuit breaker.

9. Protection Relay Test

Numerical protection relays are checked according to the approved protection settings.

Depending on the application, functions may include:

• Overcurrent protection

• Short-circuit protection

• Earth-fault protection

• Undervoltage protection

• Overvoltage protection

• Phase failure protection

• Motor protection

• Transformer feeder protection

The relay settings are compared with the approved protection coordination study or customer specifications.

10. CT & VT Test

Current transformers and voltage transformers are inspected and tested according to their specified functions.

Typical checks include:

CT:

• Ratio

• Polarity

• Wiring

• Metering core

• Protection core

• Secondary circuit

VT/PT:

• Ratio

• Polarity

• Wiring

• Secondary voltage

• Protection/metering circuits

The actual CT/VT configuration is checked against the approved protection and metering drawings.

11. Earthing Switch Test

The earthing switch is tested for correct mechanical and electrical operation.

Inspection includes:

• ON/OFF operation

• Position indication

• Mechanical interlock

• Electrical interlock

• Operating mechanism

• Grounding connection

The test confirms that the earthing switch cannot be operated in an unsafe switching position.

12. Control Circuit Test

The complete control circuit is inspected and functionally tested.

Testing may include:

• Close circuit

• Trip circuit

• Spring charging

• Breaker position indication

• Local/remote control

• Alarm circuit

• Interlocking

• Auxiliary contacts

• Control power supply

Control voltage can be tested according to the specified AC or DC system.

13. Metering & Monitoring Test

Installed metering equipment can be tested for correct connection and operation.

Typical devices include:

• Ammeter

• Voltmeter

• Multifunction power meter

• Energy meter

• Frequency meter

• Power factor meter

• Temperature monitoring system

The manufacturer can also verify communication between meters, protection relays, PLCs, and monitoring systems.

14. Communication Test

For intelligent switchgear, communication functions can be checked before shipment.

Possible interfaces include:

• RS485

• Modbus RTU

• Ethernet

• Modbus TCP

• PLC communication

• SCADA interface

Typical checks include:

• Device address

• Communication wiring

• Signal transmission

• Breaker status

• Alarm status

• Measurement data

• Remote control commands

15. Busbar Inspection

The complete busbar system is inspected for:

• Correct phase sequence

• Busbar dimensions

• Copper material

• Joint connections

• Support installation

• Insulation

• Phase identification

• Connection tightness

• Clearance requirements

The actual configuration is compared with the approved busbar layout.

16. Functional Simulation Test

The manufacturer can simulate typical operating conditions to verify the complete control and protection logic.

For example:

Normal Condition → Breaker Closed → Fault Signal → Protection Relay Operates → Breaker Trips → Alarm Activated

Other sequences can include:

• Incoming feeder failure

• Bus coupler operation

• Generator backup

• Transformer protection

• Motor feeder trip

• Earth-fault protection

• Remote trip command

17. Temperature Monitoring Test

Where temperature sensors are installed, the monitoring circuit can be checked for:

• Sensor connection

• Temperature signal

• Alarm setting

• Communication

• Display

• Trip/alarm logic where applicable

18. Partial Discharge Test — Optional

For projects with enhanced insulation monitoring requirements, partial discharge testing can be arranged according to the agreed technical specification and applicable standard.

This may be required for critical substations or projects with specific insulation diagnostic requirements.

19. FAT — Factory Acceptance Test

For EPC and utility projects, a formal Factory Acceptance Test (FAT) can be arranged before shipment.

The FAT procedure can be prepared according to:

• Customer technical specification

• Approved drawings

• Inspection & Test Plan (ITP)

• IEC requirements

• Project quality plan

• Customer inspection procedure

The customer or an appointed third-party inspection agency can participate in the FAT when specified in the contract.

20. Manufacturer Test Documentation

After testing, relevant test records can be provided, including:

• Factory Test Report

• Routine Test Report

• Insulation Resistance Test Report

• Dielectric Withstand Test Record

• Circuit Breaker Test Record

• Protection Relay Test Record

• CT/VT Test Record

• Functional Test Record

• Interlocking Test Record

• FAT Report

• Final Inspection Report

Manufacturer Testing Process

Incoming Component Inspection
↓
Assembly & Wiring Inspection
↓
Mechanical Operation Test
↓
VCB Test
↓
Earthing & Interlocking Test
↓
Insulation Resistance Test
↓
Power-Frequency Withstand Test
↓
Main Circuit Resistance Test
↓
Protection & Control Test
↓
CT/VT & Metering Test
↓
Communication & Functional Test
↓
FAT / Customer Inspection
↓
Final Inspection & Test Report
↓
Packing & Shipment

For 3kV/6kV/10kV medium-voltage switchgear, the final test scope should be established according to the specific switchgear design, applicable IEC 62271 standards, approved technical specification, and customer/EPC inspection requirements. This avoids presenting optional diagnostic tests as mandatory routine tests for every configuration.