Preface	7
	Contents	9
	1 Power Analysis	13
	1.1 Introduction	13
	1.2 Instantaneous Power	13
	1.3 Average and Apparent Power	15
	1.4 Power Factor	18
	1.5 Complex Power and Reactive Power	19
	1.6 Complex Power Balance	23
	1.7 Power Factor Correction	25
	1.8 Three-Phase System	29
	1.9 Naming Phases and Phase Sequence	30
	1.10 Star Connection	31
	1.11 Voltage and Current Relations for Y-Connection	32
	1.12 Delta or Mesh Connection	36
	1.13 Voltage and Current Relations for Delta-Connection	36
	1.14 Three-Phase Power Calculation	39
	1.15 Measurement of Three-Phase Power	44
	1.16 Power Factor Measurement	45
	1.17 Series Resonance	48
	1.18 Parallel Resonance	50
	Exercise Problems	53
	References	59
	2 Transformer: Principles and Practices	60
	2.1 Introduction	60
	2.2 Working Principle of Transformer	60
	2.3 Flux in a Transformer	61
	2.4 Ideal Transformer	62
	2.5 E.M.F. Equation of Transformer	63
	2.6 Turns Ratio of Transformer	64
	2.7 Rules for Referring Impedance	67
	2.8 Equivalent Circuit of a Transformer	69
	2.8.1 Exact Equivalent Circuit	69
	2.8.2 Approximate Equivalent Circuit	71
	2.9 Polarity of a Transformer	73
	2.10 Three-Phase Transformer	75
	2.11 Transformer Vector Group	76
	2.12 Voltage Regulation of a Transformer	84
	2.13 Efficiency of a Transformer	87
	2.14 Iron and Copper Losses	87
	2.15 Condition for Maximum Efficiency	89
	2.16 Transformer Tests	91
	2.16.1 Open Circuit Test	92
	2.16.2 Short Circuit Test	93
	2.17 Autotransformer	96
	2.18 Parallel Operation of a Single-Phase Transformer	98
	2.19 Three-Phase Transformer Connections	99
	2.19.1 Wye-Wye Connection	99
	2.19.2 Wye-Delta Connection	100
	2.19.3 Delta-Wye Connection	101
	2.19.4 Delta-Delta Connection	102
	2.20 Instrument Transformers	105
	Exercise Problems	106
	References	110
	3 Symmetrical and Unsymmetrical Faults	111
	3.1 Introduction	111
	3.2 Symmetrical Faults	111
	3.3 Unsymmetrical Faults	112
	3.4 Symmetrical Components	112
	3.5 Representation of Symmetrical Components	114
	3.6 Complex Power in Symmetrical Components	119
	3.7 Sequence Impedances of Power System Equipment	121
	3.8 Zero Sequence Models	125
	3.9 Classification of Unsymmetrical Faults	130
	3.10 Sequence Network of an Unloaded Synchronous Generator	131
	3.11 Single Line-to-Ground Fault	134
	3.12 Line-to-Line Fault	139
	3.13 Double Line-to-Ground Fault	144
	Exercise Problems	157
	References	161
	4 Grounding System Parameters and Expression of Ground Resistance	162
	4.1 Introduction	162
	4.2 Objectives of Grounding System	162
	4.3 Grounding Symbols and Classification	163
	4.4 Ungrounded Systems	164
	4.5 Grounded Systems	171
	4.5.1 Solidly Grounded System	171
	4.5.2 Resistance Grounding	176
	4.5.3 Reactance Grounding	178
	4.5.4 Voltage Transformer Grounding	179
	4.6 Resonant Grounding	180
	4.7 Ground Resistance	184
	4.8 Electric Potential	185
	4.9 Ground Resistance with Hemisphere	186
	4.10 Ground Resistance with Sphere Electrode	189
	4.11 Ground Resistance with Cylindrical Rod	191
	4.12 Ground Resistance with Circular Plate	200
	4.13 Ground Resistance with Conductor Type Electrode	205
	Exercise Problems	209
	References	210
	5 Soil Resistivity	211
	5.1 Introduction	211
	5.2 Soil Resistance and Resistivity	211
	5.3 Types of Soil	213
	5.4 Permeability and Permittivity of Soil	215
	5.5 Influence of Different Factors on Soil Resistivity	216
	5.6 Current Density of Soil	218
	5.7 Continuity of Earth Current	220
	5.8 Current Density at Soil Interface	223
	5.9 Derivation of Poisson’s and Laplace’s Equations	227
	5.10 Uniqueness Theorem	230
	5.11 Solutions of Laplace’s Equation	232
	5.11.1 One Dimension Solution	232
	5.11.2 Two-Dimension Solution	234
	5.12 Solution of Laplace’s Equation in Cylindrical Coordinates	241
	5.13 Spherical Coordinate System	243
	5.14 Solution of Poisson’s Equation	250
	5.15 Numerical Solution of Laplace’s Equation	251
	Exercise Problems	257
	References	257
	6 Soil Resistivity Measurement	259
	6.1 Introduction	259
	6.2 Two-Pole Method	259
	6.3 Four-Pole Equal Method	260
	6.4 Derivation of Resistivity	262
	6.5 Lee’s Partitioning Method	269
	6.6 Sided Probe System	271
	6.7 Schlumberger Method	273
	6.8 Different Terms in Grounding System	276
	6.9 Touch and Step Potentials	277
	Exercise Problems	282
	References	283
	7 Ground Resistance Measurement	284
	7.1 Introduction	284
	7.2 Types of Electrodes	284
	7.3 Two-Pole Method	286
	7.4 Three-Pole Method	287
	7.5 Fall of Potential Method	288
	7.6 The 62 % Method	289
	7.7 Derivation of 62 % Method	290
	7.8 Position of Probes	293
	7.9 Clamp-on Method	295
	7.10 Slope Method	297
	7.11 Ammeter-Voltmeter Method	299
	7.12 Ammeter-Wattmeter Method	300
	7.13 Wheatstone Bridge Method	300
	7.14 Bridge Method	302
	7.15 Potentiometer Method	303
	7.16 Measurement of Touch and Step Potentials	305
	7.17 Application Example 1: Measurement of Ground Resistance at Telephone Exchange	306
	7.18 Application Example 2: Measurement of Ground Resistance at Residential Area	308
	7.19 Ground Resistance Measuring Equipment	309
	References	312
	Index	313