Understanding Substation Systems and Components

Substation Layout and Design

• Comprehending the principles of substation layout, including spacing requirements, bus configurations (single bus, double bus, ring bus, breaker-and-a-half), and equipment arrangement for optimized operation and maintenance.
• Analyzing physical layouts to identify potential hazards related to clearances, access, and equipment placement.
• Applying grounding principles in substation design to ensure personnel safety and equipment protection.
• Understanding the impact of environmental conditions (temperature, humidity, altitude) on substation design and equipment selection.

Power Transformers: Operation and Maintenance

• Explaining the construction and operation of power transformers, including core types, winding arrangements, and cooling methods (oil-filled, dry-type).
• Performing transformer oil testing, including Dissolved Gas Analysis (DGA) to identify incipient faults such as overheating, partial discharge, and arcing.
• Interpreting DGA results using key gas ratios and established diagnostic techniques (e.g., Duval Triangle, Rogers Ratio).
• Executing transformer insulation resistance tests (Megger) to assess the condition of the winding insulation.
• Performing tap changer maintenance and testing, including visual inspection, contact resistance measurement, and operation cycle testing.
• Understanding and implementing transformer protection schemes, including differential protection, overcurrent protection, and sudden pressure relay operation.

Circuit Breakers: Types and Maintenance

• Identifying and understanding the operation of various circuit breaker types: Air Blast, Oil, SF6 (Sulfur Hexafluoride), and Vacuum.
• Performing routine maintenance on circuit breakers, including contact inspection, lubrication of moving parts, and gas pressure monitoring (for SF6 breakers).
• Understanding the arc quenching mechanisms of each circuit breaker type.
• Conducting timing tests to verify breaker operating speed and synchronicity of pole operation.
• Performing contact resistance measurements to assess the condition of the main contacts.
• Analyzing breaker operating records to identify trends and potential issues.

Switchgear and Disconnect Switches

• Distinguishing between different types of switchgear: metal-clad, metal-enclosed, and open-air.
• Performing visual inspections of switchgear components, including busbars, insulators, and operating mechanisms.
• Maintaining disconnect switches, including cleaning and lubrication of contacts and operating mechanisms.
• Understanding the purpose and operation of interlocks to prevent unsafe switching operations.
• Proper procedures for operating disconnect switches, including the use of hot sticks and grounding procedures.

Protection and Control Systems

Protective Relaying Principles

• Understanding the fundamental principles of protective relaying, including fault types (symmetrical and unsymmetrical), current and voltage transformers (CTs and VTs), and relay operating characteristics.
• Applying different types of protective relays, including overcurrent, differential, distance, and voltage relays, to protect various substation equipment.
• Understanding the concept of relay coordination to ensure selective tripping of protective devices.
• Calculating relay settings based on system fault levels and equipment ratings.
• Performing relay testing using secondary injection test sets to verify relay operation and settings.

Control Systems and SCADA

• Understanding the architecture and operation of substation control systems, including Remote Terminal Units (RTUs), Programmable Logic Controllers (PLCs), and Human-Machine Interfaces (HMIs).
• Interpreting SCADA (Supervisory Control and Data Acquisition) system data to monitor substation conditions and control equipment.
• Configuring and troubleshooting SCADA communication links, including serial, Ethernet, and fiber optic connections.
• Understanding the role of cybersecurity in substation control systems and implementing security measures to protect against unauthorized access and cyberattacks.
• Utilizing SCADA systems for remote control and monitoring of substation equipment.

Instrument Transformers (CTs and VTs)

• Understanding the principles of operation of current transformers (CTs) and voltage transformers (VTs).
• Performing CT ratio verification and polarity checks.
• Analyzing CT saturation curves and their impact on relay performance.
• Connecting CTs and VTs to protective relays and metering equipment.
• Understanding burden calculations for CTs and VTs.

Substation Maintenance Practices

Preventive Maintenance Strategies

• Developing and implementing preventive maintenance programs for substation equipment based on manufacturer recommendations and industry best practices.
• Performing visual inspections to identify potential problems such as corrosion, leaks, and loose connections.
• Monitoring equipment operating parameters such as temperature, voltage, and current.
• Using infrared thermography to detect hotspots in electrical connections and equipment.
• Implementing condition-based maintenance techniques to optimize maintenance schedules and reduce downtime.

Troubleshooting and Diagnostics

• Using troubleshooting techniques to identify and resolve equipment failures.
• Analyzing fault records and event logs to determine the cause of equipment trips.
• Using diagnostic equipment such as oscilloscopes, multimeters, and power quality analyzers to troubleshoot electrical problems.
• Understanding the importance of proper grounding and bonding in preventing electrical noise and equipment damage.
• Performing insulation resistance tests (Megger) to assess the condition of electrical insulation.

Safety Procedures and Regulations

• Applying substation safety rules and regulations, including lockout/tagout procedures, personal protective equipment (PPE) requirements, and safe work practices.
• Understanding the hazards associated with working near high-voltage equipment and implementing safety measures to mitigate these hazards.
• Performing ground resistance testing to ensure proper grounding of equipment.
• Understanding the requirements of the National Electrical Safety Code (NESC) and other applicable standards.
• Administering first aid and CPR in the event of an electrical accident.