IEEE P1818 / D1 Guide for the Design of Low Voltage Auxiliary Systems for Electric Power

IEEE P1818 / D1 Guide for the Design of Low Voltage Auxiliary Systems for Electric Power Substations

Master Outline

1.0Overview

1.1Scope

1.2Purpose

2.0Normative References

3.0Definitions

4.0Design of Substation AC Systems

4.1Design Criteria

4.1.1System Stability

4.1.2Customer Service and Loss of Revenue

4.1.3Equipment Protection

4.1.4Design Considerations

4.1.5Selection of Auxiliary System Voltage

4.2Station Power Source Selection

4.2.1.1Power Transformer Tertiary

4.2.1.2Substation Bus

4.2.1.3Distribution Line

4.2.1.4Standby Generators

4.3Conductor Selection

4.3.1Cable Insulation Voltage Rating

4.3.2Cable Insulation Type

4.3.3Conductor Size Calculations

4.3.3.1Required Ampacity

4.3.3.1.1Primary Conductor

4.3.3.1.2Secondary Conductor

4.3.3.2Temperature Corrections

4.3.3.3Correction for Number of Conductors

4.3.3.4Voltage Drop Verifications

4.4Station Power Transformer

4.4.1Number of the Transformers Requirements

4.4.2Single Phase or Three Phase Transformer

4.4.3Transformer Types

4.4.4Station Power Transformer Rating

4.4.4.1Load Considerations

4.4.4.2Substation AC load

4.4.4.3Transformer Rating Calculations

4.4.4.4Transformer Standard KVA Rating

4.4.4.5Transformer Connections

4.4.4.5.1Safety Considerations

4.4.4.5.2Ferroresonance Conditions

4.4.4.5.3Transformer Connections

4.4.4.5.4Transformer Impedance

4.5Transfer Switch

4.5.1General

4.5.2Manual Transfer Switch

4.5.3Automatic Transfer Switch

4.5.4Alternate Methods

4.6AC Panel Bus

4.6.1Transfer Switch to Panel Connections

4.6.2Panel Bus Rating

4.7AC Panels

4.7.1Present and Future Load Accommodation

4.7.2Load Classification (or Segregation)

4.7.3Number of Panels Required

4.7.4Panel Rating

4.8Circuit Protection

4.8.1Available Short Circuit Current

4.8.2Fault Calculations

4.8.3Transformer Protection

4.8.4Panel Protection

4.8.5Feeder Protection

4.8.6Selection of Circuit Breakers

4.8.7Selection of Circuit Fuses

4.9Equipment Specification

4.9.1NEMA Standard for Indoor/Outdoor Operation

4.10Operation and Maintenance Considerations

4.10.1Isolation Switch Requirements

4.10.2Equipment Accessibility

4.10.3Standby Backup AC System

4.10.3.1Standby Generator for System Collapse

5.0Design of Substation DC Systems

5.1Design Criteria

5.1.1Reliability

5.1.2Redundancy

5.1.3Environment

5.1.4Design Considerations

5.2Typical Equipment Served by the DC System

5.3One Line Diagram

5.3.1Number of Battery Systems

5.3.2Load Transfer

5.4DC Batteries

5.4.1Battery Types

5.4.2Criterion for Battery Rating

5.4.2.1Continuous Loads

5.4.2.2Momentary Loads

5.4.2.3Battery Voltages and Number of Cells

5.4.2.4Duty Cycle

5.5Battery Chargers

5.5.1.1Battery Charger Sizing

5.5.1.2Battery Charger Connections

5.5.1.3Charger Circuit Protection

5.6DC Panels

5.6.1Critical versus Non Critical Loads

5.6.2Circuit Size

5.7Load Transfer Methods

5.7.1Manual Transfer

5.7.2Automatic Transfer

5.8Design Considerations

5.8.1Battery Monitoring

5.8.2Battery Installation

5.8.2.1Battery Location

5.8.2.1.1Fire Considerations

5.8.2.1.2Safety Considerations

5.8.2.1.3Reliability Considerations

5.8.2.1.4Battery Room Door Requirements

5.8.2.1.5Battery Area Temperatures

5.8.2.2Acid Spill Containment

5.8.2.3Battery Racks

5.8.3Circuit Considerations

5.8.3.1Grounded versus Ungrounded Systems

5.8.3.2Isolation of Main DC Cables

5.8.3.3Circuit Protection and Coordination

5.8.3.3.1Coordination of Overcurrent Protection

5.8.3.3.2Short Circuit Levels

5.8.3.3.3Fuse and Circuit Breakers

5.8.4Equipment Rating

5.8.4.1Indoor and Outdoor Equipment Ratings

5.8.4.2Equipment Rating

5.8.5Maintenance Provisions

5.8.5.1Isolation Switches

5.8.5.2Equipment Accessibility

5.8.5.3Back-up Supplies