- Technical Paper: A Derivation of Symmetrical Component Theory and Symmetrical Component Networks (630.4KB)
Review symmetrical component analysis.
- Technical Paper: A Practical Guide for Detecting Single-Phasing on a Three-Phase Power System (864.8KB)
Reference for the loss of one or two phases of a radial three-phase system and includes suggested detection and protection methods.
- Technical Paper: A Review of Ferroresonance (518.8KB)
The basics of a ferroresonant condition.
- Technical Paper: A Review of High-Impedance and Low-Impedance Differential Relaying for Bus Protection (311.4KB)
Fundamentals of bus protection with a focus on high-impedance and low-impedance bus differential relaying.
- Technical Paper: A Review of Negative-Sequence Current (273.2KB)
Negative-sequence current and the damage it can cause to rotating machines.
- Technical Paper: A Review of System-Grounding Methods and Zero-Sequence Current Sources (762.3KB)
Grounding methods, sources of ground current, ground-current flow in the power system, and how each impacts protective relaying.
- Technical Paper: A Review of Wye/Delta Transformer Connections and How They Affect Measured Current and Voltage (507.3KB)
The transformer is arguably one of the key technologies that led to AC winning over DC in the contest to distribute electricity across the US and the world.
- Technical Paper: A Survey of Cold Load Pickup Practices (668.6KB)
Cold load pickup, the causes and effects.
- Technical Paper: Analysis of Transformer Inrush Current and Comparison of Harmonic Restraint Methods in Transformer Protection (951.7KB)
Factors affecting the second-harmonic ratio in inrush current and various harmonic restraint methods.
- Technical Paper: Application of Islanding Protection for Industrial- and Commercial-Generators (592.1KB)
Issues associated with the islanding of an industrial- or commercial-facility power system where a synchronous generator operates in parallel with the utility source.
- Technical Paper: Arc Flash Mitigation Through Use of Voltage Controlled/Voltage Restrained Overcurrent Elements (244.2KB)
The use of voltage controlled/voltage restrained overcurrent elements as an arc flash mitigation technique.
- Technical Paper: Automatic Reclosing - Transmission Line Applications and Consideration (1.2MB)
Applying autoreclosing to transmission circuits.
- Technical Paper: Breaker Monitoring with Numerical Relays (392KB)
Breaker duty/contact wear monitoring.
- Technical Paper: Bus-Protective Relaying, Methods and Application (1.5MB)
Application of bus-protective relaying, describing and comparing differences.
- Technical Paper: Choosing the Correct Transfer Switch (171.6KB)
For effective ground-fault protection, transfer switch must be chosen at project beginning.
- Technical Paper: Commissioning Numerical Relays (681.2KB)
Experienced-based changes to commissioning tests and revised documentation of settings as a method for commissioning.
- Technical Paper: Considerations for Effective RS-485 Network Design (169.1KB)
Considerations for effective RS-485 network design.
- Technical Paper: Current Transformer Errors and Transformer Inrush as Measured by Magnetic, Optical and other Unconventional CTs (1MB)
Errors in secondary current for these primary current conditions determine when CTs are at risk, and show, using numerical analysis, the output of a saturated CT.
- Technical Paper: Directional Overcurrent Relaying in the Distributed Generation Environment (1MB)
Basics of directional overcurrent relaying as applied in modern numeric relays.
- Technical Paper: Distributive Generation and Interconnection: Protection, Monitoring, and Interconnection Opportunities (1.4MB)
Paralleling a distributed-generation supply to an electric power system involves protection, monitoring and control of the interconnection.
- Technical Paper: Effects of Distributed Generation on Utility Protection Schemes (383.3KB)
Addition of distributed generation to a distribution feeder can be minimized by having digital multifunction overcurrent with voltage-protection schemes.
- Technical Paper: Extending Motor Life with Updated Thermal Model Overload Protection (518.8KB)
Updates in the 49 thermal model provide better motor protection.
- Technical Paper: Fundamentals and Advances in Breaker-Failure Protection (703.4KB)
Deciding whether to apply dedicated breaker failure protection.
- Technical Paper: Get in Step with Synchronization (318.5KB)
Review of power-system synchronization.
- Technical Paper: Green Power - Wind Generated Protection and Control Considerations (1011.8KB)
Green power projects like wind farms allow protection and control engineers to use modern technology to provide cost effective systems.
- Technical Paper: Ground Differential Protection: Revisited (265.3KB)
Principles of ground differential protection within industrial power systems.
- Technical Paper: Harmonic Sharing for Effective Detection of Transformer Inrush Condition in Differential Protection Scheme (564KB)
Harmonic sharing in transformer differential protection improves security for some inrush conditions, while maintaining sensitivity.
- Technical Paper: Intertie Requirements for DGs Connected to Radial-Distribution Feeders (138.7KB)
Proposed protection requirements for distributed generation connected to radial-distribution feeders.
- Technical Paper: Introduction to Synchronizing (181.5KB)
Automatic synchronizing process and a guide for selection of the proper synchronizer.
- Technical Paper: Life Lessons from the Power System (681.3KB)
Explores the basic principles of relay protection design and relay protection commissioning, while reflecting upon lessons learned.
- Technical Paper: Load Shedding for Utility and Industrial Power System Reliability (572.6KB)
Analysis of the conditions in which load shedding may be needed and review of load shed implementation strategies.
- Technical Paper: Myths of Protecting the Distributed Resource To Electric Power System Interconnection (739.4KB)
For the ideology of power-system protection, the myths described in this paper are better described as conditional truths rather than half-truths.
- Technical Paper: Negative-Sequence Relaying Applications in Ungrounded and High-Impedance Grounded Industrial Systems (591.4KB)
Negative-sequence overcurrent sensing to detect faults.
- Technical Paper: New Methods for Detecting Unintentional Islanding for a Distributed-Generation Inverter (452.6KB)
Islanding testing for an inverter driven by a high-speed, magnetic-levitation generator powered by waste heat from industrial processes.
- Technical Paper: Power Quality: Measurement of Sags and Interruptions (362.9KB)
Measurement of power quality use of meters for residential and small commercial customers as a tool to track outage issues.
- Technical Paper: Practical Experience in Commissioning Distributed Generation Installations (171.7KB)
Commissioning several distributed generation projects under the auspices of Portland General Electric's Dispatchable Generation Program.
- Technical Paper: Predicting Current Differential Relay Tripping (1.6MB)
Testing current differential relays at final settings.
- Technical Paper: Protection Considerations for Installation of Distributed Energy Resources (569.6KB)
This tutorial addresses issues often encountered by utility engineers and Distributed Energy Resources (DER) consultants or developers when negotiating intertie protection requirements between the DER and electric utility.
- Technical Paper: Protective Relaying Issues in Low-Voltage Systems as Addressed in the National Electric Code (1.2MB)
Low Voltage (LV) design practices, as mentioned in the National Electric Code (NEC).
- Technical Paper: Protective Relaying Methods for Reducing Arc-Flash Energy (653.1KB)
Arc flash standards/requirements and high-speed detection and operation techniques used to reduce arc-flash energy via protective relays.
- Technical Paper: Protective Relaying When Distributed Generation is Added to Your Circuit (474.5KB)
Advantages of having numeric multifunction protection in place when distributed generation is added to a radial-distribution circuit.
- Technical Paper: Reliability Considerations of Multifunction Protection (331KB)
Reliability of numerical multifunction protection systems against predecessor technologies.
- Technical Paper: Solutions for Unconventional Connection of Transformer Differential Current Transformers (982.3KB)
Analyzing unconventional current-transformer polarity connections and how to obtain the right connection to achieve the desired direction of operation or polarity.
- Technical Paper: Successful DG Projects: Design and Build Considerations (869.2KB)
Design and build challenges for four DG projects.
- Technical Paper: Synchronous Motor Control (579.6KB)
Basic theory of operation and control of the synchronous motor.
- Technical Paper: Three Phase Transformer Winding Configurations and Differential Relay Compensation (1.2MB)
How a transformer differential relay compensates for the effects of the various transformer winding configurations.
- Technical Paper: Upgrading Intertie Protection to meet TX PU Standards (343.9KB)
Utilizing multifunction relays as the sole means of protection, not only for the plant and its generation, but also for the utility.
- Technical Paper: Upgrading Relay Protection? - Be Prepared. (336.4KB)
Guidance for your next replacement or upgrade project.
- Technical Paper: Using GOOSE Messages in a Main-Tie-Main Scheme (499.5KB)
Main-tie-main circuit breaker bus switching scheme performed using IEC 61850 GOOSE messaging.
- Technical Paper: Using Iop Characteristics to Troubleshoot Transformer Differential Relay Misoperation (1.2MB)
Transformer differential false trips and methods to alleviate this issue.
- Technical Paper: Voltage Restrained Time Overcurrent Relay Principles, Coordination, and Dynamic Testing Considerations (330.1KB)
Dynamic response of 51/27R relays in which the overcurrent element conforms to the dynamic characteristic defined in ANSI C37.112.
- Technical Paper: Who has the 32? (2.8MB)
Understanding Directional Power (ANSI device number 32) protection.
- Technical Paper: Zero-Sequence Circuit of Three-Legged Core Type Transformers (648.5KB)
Modified zero-sequence equivalent circuit for a three-legged core-type transformer.
- Technical Paper: Zero-Sequence Impedance of Overhead Transmission Lines (716.5KB)
Transmission-line impedances, centering on zero-sequence impedances.