HIGH VOLTAGE SWITCHGEAR

Course Description

This course will present a comprehensive capsule of all the knowledge essential for the medium voltage and high voltage equipment and switchgear operations and walk the participants through the switchgear design process using a set of interlinked case studies. The course focuses mainly on the operation and maintenance of distribution equipment namely transformers, circuit breakers, contactors, isolators and disconnectors, also include the auxiliary control circuits.

Medium and high voltages equipment and switchgears are the integral component of any electrical distribution system; hence, the selection and installation of these equipment and switchgears are vital so as to provide protection and safe distribution of electrical power. The equipment needs to be operated in a safe manner securing continuity of supply to consumers.

OBJECTIVE

• Understanding the types of medium voltage and high voltage equipment and switchgears
• Operation principle of medium voltage equipment and circuit breakers
• Identification of the various types of high voltage equipment and switchgears
• Maintenance of testing of equipment and switchgears
• Construction and operations of high voltage transformers, equipment and switchgears

COURSE CONTENS

1. Power and Distribution Transformer Operations

2. Generator and Motor Operations

3. Power Substation and Equipment

4. Circuit Breaker Technologies

- Arc Phenomenon, Interruption, Arcing

- Bulk Oil Circuit Breakers (BOCBs)

- Minimum Oil Circuit Breakers (MOCBs)

- Air Circuit Breakers (ACBs)

- Air Blast Circuit Breakers (ABCBs)

- SF6 Gas Circuit Breakers

- Vacuum Circuit Breakers (VCBs)

- Gas Insulated Switchgear (GIS)

- Circuit Breaker Operating Mechanisms

- Motor-driven Mechanisms

5. Medium Voltage Switchgear

- Metal-enclosed Switchgears

- Live Tank Switchgears (Outdoor Porcelain-clad Construction)

- Design Parameters

- Normal Current Rating (Thermal Aspects of Design)

- Short-circuit Current

- Insulation Aspects of Design

- Vacuum Switchgear

6. High Voltage Circuit Breaker

- Classification of Circuit Breakers

- Operating Mechanisms for Circuit Breakers

- Spring Mechanism

- Pneumatic Mechanism

- Hydraulic Mechanism

- SF6 Gas Dynamic Mechanism

- Motor-driven Mechanisms

- Comparison of Operating Mechanisms

7. Current Transformers and Voltage Transformers

- Theory of Current Transformers

- Theory of Voltage Transformers

- Technical Parameters of Instrument Transformers

- Types of Instrument Transformers

- Types of Voltage Transformers

- Some Important Design Considerations

- Application of Instrument Transformers in Various Protection Schemes

- Instrument Transformer Testing and Analysis of Test Results

- Standardisation and Cost Considerations of CTs and VTs

- Field Performance of Instrument Transformers

8. Surge Protection

- Surge Protection Devices

- Metal Oxide Type Surge Arrester

- Capacitance Resistance (C-R) Type Surge Suppressor

- Application of Surge Protection Devices

- Over-voltages in Sub-stations

- Location of Arrester

- Performance Evaluation

- Performance Monitoring of Surge Protection Devices

- Surge Counters

- Measurement of the Leakage Current

9. Application of Medium Voltage Switchgear

- Various Considerations

- Location Considerations

- Rating Considerations

- Ambient Considerations

- System Earthing Considerations

- Over-voltage Considerations

- Application of Switchgears in Power System

- Generator Circuit Breakers

- Switchgears for Power Plant Auxiliaries

- Switchgears for Transmission Sub-stations

- Switchgears for Distribution Applications

- Switchgears for Industrial Applications

- Control and Interlocking Schemes for Medium Voltage Switchgear

- Protection Schemes for Medium Voltage Switchgear

10. Erection and Commissioning of Switchgears

- Outdoor Switchgears

- Indoor Switchgears

- Installation

- Erection

- Assembly

- Filling with Insulation Medium

- Earthing

- Final Inspection

- Testing and Commissioning

- Visual Inspection Check

- Mechanical Check

- Electrical Check

- Operational Check

- Insulation Resistance Check

- High Voltage Check

- Final Commissioning/Load Testing

11. Operation and Maintenance of Switchgear

- Operation of Switchgear

- Switchgear Maintenance

- Maintenance Requirements

- Inspection Schedule

- Preparation Before Maintenance

- Maintenance Procedure

- Switchgear Spares

- Lubrication of Operating Mechanism

- Troubleshooting Guide

- Service Feedback

12. Testing of Switchgears

- Routine Tests

- Dielectric Test on the Main Circuit

- Dielectric Test on Auxiliary and Control Circuits

- Measurement of the Resistance of the Main Circuit

- Tightness Test

- Design and Visual Checks

- Mechanical Operation Tests

- Type Tests

- Dielectric Tests

- Radio Interference Test

- Measurement of the Resistance of Main Circuit

- Temperature Rise Test

- Short Time Current Withstand Test

- Verification of the Degree of Protection Test

- Electromagnetic Compatibility (EMC) Test

- Mechanical Operation Tests at Ambient Temperature

- Short-circuit Duties Test

- Capacitive Current Switching Tests

- Environmental Test

- Critical Current Test

- Short Line Fault Test

- Special Tests