Protective Device Coordination Course Topics

A detailed outline of all presentation slide topics can be found here.

New topics: Distributed Energy Systems

The implementation of distributed energy sources such as wind and solar to system protection and coordination is challenging the engineering for protection and coordination within utility distribution systems. Protection can be complex because what was once a single source distribution system is now a multi-source network with challenges comparable to transmission level grid systems.

Current Topics

System Analysis

Fault current and load flow calculations using computer software

Effects of faults to areas remote from the fault

Overview of hand calculation methods such as per-unit and symmetrical component analysis

Important symmetrical component relationships to systems and equipment

Power quality constraints on device coordination.

Protection of equipment with current limiting fuses and breakers

Protection of control equipment with low SCCR ratings

Protective Device Coordination Principles

Graphical tools and time/current curve interpretation

Load flow and unbalanced fault effects

Cold load pickup

Grounding system constraints

Coordination economics

Asymmetrical current impacts

Coordination time intervals

Transformer effects on coordination

Software and graphical tool limitations

Current transformer performance and selection

Arc Flash Studies

Arc flash computations

Personal protective equipment

NFPA 70E vs. IEEE 1584 computations

Arc flash vs. Device coordination

Arc flash study rules-of-thumb to minimize study costs

Arc blast protection and impacts of equipment design on protective device coordination

Equipment And Device Characteristics

Fuses - low voltage and medium voltage

Molded case and insulated case breakers

Solid-state trip low voltage breakers

Equipment damage characteristics

Proper protective device selection

High voltage breakers

Low voltage cable protection

Shielded cable protection

Overhead conductor protection

Motor protection

Generator protection

Transformer protection

Panelboard and switchgear protection

Inverse time/overcurrent protective relays and instantaneous trip devices

Series rated breakers

Differential and voltage constrained relays

Zone interlocking of breakers and relays

Reclosing relays, reclosers, and sectionalizers

Electromechanical and digital relay performance realities

Current transformer characteristics, selection, and calculations

Ground Fault Protection

Arcing ground fault magnitudes

Ground fault protection schemes

Interaction of ground fault relays and phase overcurrent devices

Emergency Power System Design

Weak Source Systems

Generator fault characteristics

Uninterruptible power supply (UPS) fault characteristics

Transfer and static switch limitations

Improving emergency circuit design

Impact of Distributed Energy Sources on Protection and Coordination

Common Coordination Problems, Errors, And Misconceptions

Preliminary System One-Line Development For A Coordinated System

Designing Systems For Minimizing Arc Flash Hazards

Lessons Learned And “Rules Of Thumb” To Spot Uncoordinated Systems And Methods To Develop A Coordinated System Design

Criteria Impacting Coordination

NESC, I.E.E.E. Std C2,

NFPA 70-National Electrical Code

NFPA 70E - (Arc Flash Protection Of Employees)

Military UFC and FAA criteria (this material is only added for those students who are government employees or consultants to the government)

Switchgear And Relay Commissioning

Hands-On Lab Exercises

Student calibration of a relay (student will actually run the test set and compare performance against relay curves)

Transformer testing by students to determine transformer impedances and compare actual results to per-unit computations with various tap configurations

8 classroom hours will be used to work example design problems with student involvement in the following system types. Students are encouraged to bring their own system problems for class analysis.

Low voltage system with critical systems fed from normal and emergency power sources

Medium voltage system from a 15 kv class substation primary to the low voltage secondary

Note: no software will be used or required of the student. The instructor will use software during presentation to analyze the systems and devices selected by the students.

 Specification Writing for a Coordinated System