APPLICATION OF PROTECTIVE RELAYS USED FOR ABNORMAL FREQUENCY LOAD SHEDDING AND RESTORATION
Institute of Electrical & Electronics Engineers
1 Overview
1.1 Scope
1.2 Purpose
2 Normative References
3 Description of system conditions addressed in this guide
4 Normal and abnormal frequency operation of electrical power
systems and its effect on equipment in the system
4.1 Power system dynamic
4.2 Abnormal frequency operation of power systems
5 Underfrequency load shedding and restoration philosophy
6 Underfrequency load shedding methods
6.1 Manual/SCADA load shedding
6.2 Automatic load shedding
6.3 Local
6.4 Wide area underfrequency load shedding
7 Load restoration methods
8 Frequency relays, measuring principles, and characteristics
8.1 Electromechanical relays
8.2 Solid-state (static) relays
8.3 Microprocessor (digital) relays
9 Operating principles
9.1 Fixed frequency
9.2 Rate of change of frequency df/dt
9.3 Average rate of change f/t
10 Scheme design
10.1 Dependability and security
10.2 Redundant frequency relays sensing multiple voltage sources
10.3 Current and voltage supervision
10.4 Directional power supervision
10.5 Rate-of-frequency-change supervision
11 Effects of voltage change on frequency load shedding
12 Existing frequency load shedding and restoration practices
12.1 NERC: 2003 underfrequency load shed criteria
12.2 Nordel underfrequency load shed criteria
12.3 France, Electricite de France underfrequency load shedding
12.4 Ireland, Electricity Supply Board underfrequency load
shedding and automatic frequency restoration
12.5 Industrial applications
13 Setting and performance criteria
13.1 Performance criteria
13.2 Setting guidelines for abnormal frequency load shedding
14 Maintenance, testing, and reliability
14.1 Frequency protection elements
14.2 Rate-of-change elements
14.3 Average rate-of-change elements
14.4 Testing of load shedding schemes
14.5 Testing of load restoration schemes
15 Examples
15.1 Practical application of load shedding
15.2 Historical examples of underfrequency load shedding
during system disturbances
Annex A (informative) Bibliography
Describes abnormal frequency power system behavior, existing load shedding and restoration practices, the abnormal frequency function of typical protective relays, and possible new methods for improved load shedding and restoration.
| Document Type | Standard |
| Status | Current |
| Publisher | Institute of Electrical & Electronics Engineers |
| Supersedes |
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