Protection of Electrical Power Systems
Overview:
Introduction:
Power system protection is an essential component of all forms of electrical power systems. In practice, protective relaying is directly associated with security of supply, the reduction of damage to the faulted plant, the cost of energy, and, most importantly, all aspects of safety. The subject is unique in requiring knowledge of all topics broadly classified under the title of electrical power engineering, including generation, utilization, maintenance, and the transmission of electrical power. As a consequence, it enhances an engineer’s working knowledge and becomes an important asset for power system planning, operation, and management.
The course focuses attention on the fundaments of the subject and illustrates the protection philosophies in common use by reference to the application of modern multi-functional microprocessor relays to practical situations illustrated by case studies.
Course Objectives:
At the end of this course, the participants will be able to:
- Understand the need for protection
- Have an overview of power system fault analysis
- Learn about the protection fundamentals
- Relay transducers, both current and future
- Understand the system grounding principles
- Overcurrent earth fault protection
- Learn about the coordination principles
- Learn about the transformer protection
- Learn about generator protection
- Understand the bus protection
- Learn about the motor protection
- Learn about the line and feeder protection
- Learn about the principles of relay application
Targeted Audience:
- Electrical/Plant Engineers
- Supervisors
- Technicians
- Electricians with responsibility for the application
- Commissioning and/or maintenance of electrical protective equipment used on the industrial electrical power system
Course Outlines:
Unit 1: Fundamentals and Fault Analysis:
- Introduction to power system protection
- Power system fault analysis
- Phase faults
- Earth faults
- Manual calculation
- Use of software
- Case study
- Protection fundamentals
- Definitions and terminology
- Unit and non-unit systems
- Wrap up session
Unit 2: Transducers and Overcurrent Schemes:
- Transducers
- Current transformer (CT) equivalent circuit
- CT specification
- CT errors
- CT characteristics
- Effect of CT burden
- Overcurrent relays of control systems
- The modern relay and functions provided
- Characteristics
- Directional schemes
- High and low set instantaneous relays
- Application to earth faults
- Principles of coordination
- Case studies and tutorials
Unit 3: Unit Protection 1:
- Transformer protection
- Typical transformer faults
- Protection of small transformers
- Biased differential
- High impedance differential
- Restricted earth leakage
- Buchholz and winding temperature
- Additional earth fault
- Use of earthling transformer
- Relay settings for modern multi-functional relays
- Generator and generator unit
- Schematic layout of the plant
- Generator grounding principles
- Generator earth fault
- Differential schemes
- Discussions and wrap up session
Unit 4: Unit Protection 2:
- Generator protection continued
- Asynchronous running
- Negative phase sequence
- Over and under-voltage
- Over and under frequency
- Reverse power
- Excitation
- Motor protection
- Motor protection principles
- Thermal considerations
- Frequent starting
- Locked rotor
- Phase imbalance
- Single phasing
- Phase short circuit
- Earth fault
- Undercurrent
- The setting of multifunctional relays
Unit 5: Bus and Circuit Protection:
-
Busbar protection
- Principles of operation
- High impedance selective schemes
- Tutorial
- Distance protection
- Principles of operation
- Characteristics
- Arcing faults
- Faults close to relay location
- Causes of the inaccuracy of measurement
- Teed feeders
- Practical study