Power Plant Protection Track - Beckwith Protection & Control Seminar 2026

Generator Protection – IEEE C37.102

Generators are subject to internal faults, external faults and abnormal operating conditions impressed by turbine and excitation system issues, as well as power system events the generator has no control over but must cope with. False (nuisance) trips are costly as the generator’s output is lost. Inability to trip due to lack of sensitivity, lack of certain protections or deficiencies in protection application may cause severe damage to generators, resulting in prolonged outage and revenue loss, plus increased system stability risk. Achieving the ideal balance of secure and dependable protection involves use of an array of elements that protect the generator for all operating modes: off-line, start up, synchronizing, various levels of power output and when challenged by system faults and anomalies.

Generator construction and operation
Grounding and connections
IEEE standards for generator protection
- IEEE C37.102 (Guide for AC Generator Protection)
Generator and power system interaction
Generator protection element overview
- Internal faults (in the generator zone)
- Abnormal operating conditions
- External faults
Protection Application Exploration
- Stator Ground Fault (27TN, 59N, 59D, 64S, 67N, 87GD)
- Exploration of stator ground fault injection protection sensitivity and security
- Rotor Ground Fault/Brush Lift Off (64F, 64B)
- Stator Phase Fault (87G)
- Turn-to-Turn Fault
- Phase Unbalance/Open Conductor (46)
- Overexcitation (24)
- Abnormal Voltage (59)
- Phase Fault Backup (21)
- Field Loss (40)
- Loss of Synchronism (78)
- Abnormal Frequency (81-U, 81A)
- Inadvertent Energizing (50/27)
- Blown VT Fuses (60FL)
- Breaker Failure/Pole Flashover (50BF)
- Loss of Prime Mover (32)
Tripping considerations and sequential tripping
Discuss tactics to improve reliability (security & dependability)
Generator protection upgrade considerations & Redundancy concepts
Explore Setting, Commissioning and Event Investigation Tools

Transformer Protection – IEEE C37.91

Transformers are subject to internal faults, the effects of external faults and abnormal operating conditions impressed by the power system events the transformer has no control over but must cope with. False (nuisance) trips are costly as the transformer and load are disconnected. Inability to trip due to lack of sensitivity, lack of certain protections or deficiencies in protection application may cause severe damage to transformers, negatively impacting power flows, impacting power quality and compromising stability. Achieving the ideal balance of secure and dependable protection involves use of an array of elements that protect the transformer from prolonged internal faults, excessive through faults and when challenged by power system faults and anomalies.

IEEE C37.91 (Guide for Protecting Power Transformers)
IEEE Devices used in Transformer Protection
Transformer Protection Review & Functions
Explore Protection Functions
87T Phase Differential Characteristic
Compensation in Digital Relays
Relay Configuration: Winding Arrangement and CT Connection
Overcurrent based (50, 51, 50N, 51N, 46)
Through fault protection (TFM)
Overexcitation (24)
Generating plant causes
T&D system causes
Protection Against Overexcitation – V/Hz versus 5th Harmonic
Phase Differential (87T)
Unique Issues Applying to Transformer Differential Protection
CT performance issues (saturation, remnant flux, tolerance, rating)
Percentage differential characteristics with variable percentage slopes
Internal ground fault sensitivity
Restraints for inrush and overexcitation
Overexcitation 87T Blocking Restraint – Failure to detect nascent fault
Overexcitation Adaptive 87T Pickup Restraint – Detects nascent faults
Adaptive restraint for security
Point-on-Wave Switching Inrush
Cross Phase Averaging
Switch-onto-Fault
High Set Phase Differential (87H)
Ground Differential (87GD), Restricted Earth Fault (REF)
Interface and Analysis Software: Desirable Attributes
NERC “State of Reliability”

Transformer Protection Calculations & Settings

Building on the base knowledge covered in Transformer Protection Fundamentals, calculations for protective elements are developed. Depending on the element, these calculations use nameplate data, system data or a combination of the two. Margin considerations are explored and impacts on element reliability are discussed, as well as element interdependencies with protection and control in the transformer zone, whether in generation, transmission or distribution.

Motor Bus Transfer

Motor Bus Transfer is the process of rapidly transferring sources to a motor bus for planned source switching and unplanned source failure. The rapid transfer allows the process to continue without interruption. To avoid damage to the motors, specialized equipment and methods are employed to cope with the dynamics of motor deceleration, and voltage and phase angle change between the new source and the motor bus. Improper reconnection of the motor bus can cause cumulative or immediate damage to the motors, and result in a process crash.

Why Transfer Motor Load Sources
Basic Application Configurations
- Primary-Backup
- Main-Tie-Main
- Multiple-Option Source Selection
IEEE Std C37.96-2012 Motor Bus Transfer Classification – Methods & Modes
- Automatic and Manual
- Closed Transition Method – Hot Parallel Transfer
- Open Transition Method – Fast, In-Phase, Residual Voltage
- Open Transition Modes – Simultaneous, Sequential
IEEE Std C37.96-2012 Conditions Across Normally Open Startup or Bus Tie Breaker – Before / During Transfer
- Effects of a Fault
- Out-of-Step (OOS) Generator Trip
- System Separation between Incoming Supply Sources
- Supply Source Transformer Winding Phase Shift
- Transient Effects upon Disconnect of Motor Loads
- Motor and Load Characteristic Effects on MBT
Transfer Initiate, Inadvertent External Operation, Lockouts
Load Shed During Transfer
ANSI/NEMA Standard C50.41-2012
Bus Transfer Spin Down Testing, Acceptance Testing, Setting Considerations

Power Quality (PQ) Metering

Maintaining high power quality is essential to energy efficiency and energy cost management, as well as customer satisfaction. Low power quality can damage equipment, cause data loss or corruption, and result in costly power outages. International standards such as IEC 61000-4-30 establish power quality parameters that must be adhered to and processes for measuring the parameters. Meters that are certified to the IEC 61000-4-30 standard have demonstrated their ability to accurately measure the standard’s power quality parameters. Power quality meters must also provide alarm/limit capabilities and waveform recording for after event analysis. EN 50160 reporting is an important feature for meters sold in the European market. It gives the main characteristics of the grid voltage at the customer’s supply terminal under normal operating conditions.