Distribution Protection Track - Beckwith Protection & Control Seminar 2026

Distribution Feeder Protection & Control

Distribution protection is a complex scenario with many elements: relayed feeder breakers, recloser controlled feeder breakers, line reclosers, sectionalizing switches, sectionalizers and fuses. The application and location of the protective and sectionalizing infrastructure predicates the application and coordination of protection. Compounding the complexity is the application of DMS/DA and presence of DER/DG. The session covers the distribution topology and protective infrastructure, and application of settable of relays and recloser controls.

Fault Calculations and Settings
Protection Devices and Characteristics
Protective Device Selection and Application
Protective Functions of Relays and Controls
Ground Fault Detection Method
Automatic Reclosing
Time Overcurrent Device Coordination
Special Protective Applications
Fault Event Analysis

Distribution Automation: FLISR

This session will focus on various Fault, Location, Isolation, and Service Restoration (FLISR) schemes. FLISR is utilized to limit the number of customers affected by a permanent fault by isolating the fault and utilize other sources to reconfigure the system to restore as many customers as possible. The proliferation of Distributed Energy Resources (DER) also needs to be taken into account with distribution automation. These schemes vary in complexity from simple throw over, to more complex loops utilizing peer-to-peer IED communication, and the most advanced that incorporates system models. Scripted or logic-based FLISR schemes will be compared to ones that incorporate system models, from more simplistic models to full Geographic Information Systems (GIS) integration.

Distributed Energy Resources Operation, Control & Protection – IEEE 1547

Distributed Electric Resource (DER) is increasing its penetration into the distribution system. This technical session provides a background into DER operation and associated control and protection considerations for conventional and inverter-based power sources. We will review types of DER/DG and the modes in which they can operate in parallel with the distribution system. Key aspects of IEEE 1547 and a sample DER interconnection screening process are highlighted. Details of on-site standby power system conversion to operate in parallel with the distribution system are shown. Protection methodology at the point-of-common coupling (PCC) and point-of-interconnection (PI) is explored for all types of DER. A treatment of distribution system protection and control considerations and applications with DER is discussed.

Define Distributed Electrical Resource (DER)
Explore Types of DERs
Why DER?
Utility and Facility Drivers for DER
Mission Critical Power and Conversion to DER
Rates and DER Operational Sequences
Industry Concerns
IEEE 1547 (Standard for Interconnection and Interoperability of Distributed Energy Resources with Associated Electric Power Systems Interfaces)
Sample Utility DER Interconnection Guide
Interconnection Protection: “The Five Food Groups”
- Anti-islanding
- Powerflow
- Fault detection
- Abnormal operating conditions
- Reconnection
Interconnection Transformer Impacts
Generator Types and Impacts
- Synchronous
- Induction
- Asynchronous (Inverter Based)
Example Protection Applications
Distribution Protection Coordination Issues
- Directionalization
- Reclosing coordination
Smart Grid / Microgrid and DER
Impact of IEEE 1547-2018
- Fault ride-through
- Reactive support and voltage control
System Control with DER
- LTC, Regulator and Capacitor Control Issues

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.