Irwin Lazar — Electrical Systems Analysis and Design for Industrial Plants B-1

Electrical Systems Analysisand Design for Industrial

Plants

Irwin Lazar

Irwin Lazar — Electrical Systems Analysis and Design for Industrial Plants B-2

Irwin Lazar — Electrical Systems Analysis and Design for Industrial Plants B-3

Irwin Lazar — Electrical Systems Analysis and Design for Industrial Plants B-4

Irwin Lazar — Electrical Systems Analysis and Design for Industrial Plants B-5

PATH OF ELECTRICAL CURRENT

BOTH BREAKERS TRIP OUT

SECOND �GROUND FAULT

FIRST �GROUND FAULT

SECONDARY WINDING

FIGURE 3. DOUBLE LINE TO GROUND FAULT ON UNDERGROUND SYSTEMS RESULT IN �OUTAGES OF TWO CIRCUITS AND HIGH LEVEL FAULT CURRENTS CAUSING SEVERE �EQUIPMENT DAMAGE

FULL LINE-TO-LINE VOLTAGE

NORMAL LINE-TO-GROUND �VOLTAGE

NEUTRAL

GROUND POTENTIAL

NUETRAL

LINE-TO-GROUD VOLTAGE �DURING FAULT (EQUAL TO �FULL LINE-TO-LINE VOLTAGE

A. NO FAULT SYSTEM�(NEUTRAL FLOATS AT GROUND POTENTIAL

B. SINGLE LINE-TO-GROUND FAULT ON SYSTEM�(ONE LINE AT GROUND POTENTIAL

FIGURE 4 LINE-TO-GROUND VOLTAGES FOR A SINGLE LINE-TO-GROUND FAULT �ON AN UNDERGROUND NEUTRAL SYSTEM

Irwin Lazar — Electrical Systems Analysis and Design for Industrial Plants B-6

Irwin Lazar — Electrical Systems Analysis and Design for Industrial Plants B-7

Irwin Lazar — Electrical Systems Analysis and Design for Industrial Plants B-8

Irwin Lazar — Electrical Systems Analysis and Design for Industrial Plants B-9

Irwin Lazar — Electrical Systems Analysis and Design for Industrial Plants B-10

Irwin Lazar — Electrical Systems Analysis and Design for Industrial Plants B-11

Irwin Lazar — Electrical Systems Analysis and Design for Industrial Plants B-12

Irwin Lazar — Electrical Systems Analysis and Design for Industrial Plants B-13