Table of Contents
Cover
Title Page
Copyright
Preface
Chapter 1: Overvoltage Mechanisms in Power Systems
1.1 Electromagnetic Transients and Overvoltage Classification
1.2 Overvoltage Classification in Power Systems
1.3 Atmospheric Overvoltages
1.4 Switching Overvoltages
1.5 Power Frequency Overvoltages
1.6 Resonance Overvoltages
Chapter 2: Transducers for Online Overvoltage Monitoring
2.1 Overvoltage Transducers at Transformer Bushing Taps
2.2 Gapless MOA Voltage Transducers
2.3 Voltage Transducers for Transmission Lines
2.4 Full-Waveform Optical Online Monitoring Technology
Chapter 3: Online Overvoltage Monitoring System
3.1 Overview
3.2 The Structure of Overvoltage Monitoring Systems
3.3 Acquisition Devices of Overvoltage Monitoring Systems
3.4 Overvoltage Signal Transmission System
3.5 Overvoltage Waveform Analysis System
3.6 Remote Terminal Analysis System for Overvoltage Waveforms
3.7 Case Study of Online Overvoltage Measurements
3.8 Statistical Analysis of Overvoltages
Chapter 4: Wave Process of Incoming Surges and Transient Response Characteristics
4.1 Current State of Incoming Surge Research
4.2 Wave Process under Complex Conditions
4.3 Generation of Lightning Overvoltages on Electrical Equipment
4.4 Simulation of Incoming Surges in Substations
4.5 Influencing Factors of Substation Incoming Surges
4.6 Typical Waveforms of Substation Incoming Surges
4.7 Response Characteristics of Lightning Overvoltages Propagating in the Grid
4.8 Lightning Location System (LLS)
Chapter 5: Typical Field Tests and Waveform Analysis in UHVDC Transmission Systems
5.1 Waveform Acquisition and Analysis in Typical Tests
5.2 Typical Field Tests for the UHVDC Transmission System
Chapter 6: Overvoltage Digital Simulation
6.1 Overvoltage Digital Simulation Software
6.2 Evaluation of Switching Overvoltages
6.3 Evaluation of Power Frequency Overvoltages
6.4 Evaluation of Atmospheric Overvoltages
6.5 Evaluation of Ferro-Resonance Overvoltages
6.6 Evaluation of Very-Fast Transient Overvoltages
Chapter 7: Entity Dynamic Simulation of Overvoltages
7.1 Overview
7.2 Modeling Methods for Transmission Line Lightning Channels
7.3 Verification of Simulated Transmission Line Lightning Channels
7.4 Dynamic Simulation Testing System
Chapter 8: Overvoltage Pattern Recognition in Power Systems
8.1 Selection of Characteristic Values
8.2 Time-Domain Characteristic Extraction
8.3 Wavelet Transform Analysis
8.4 Singular Value Decomposition (SVD) Theory
8.5 Characteristic Value Selection for Sorters
8.6 SVM-Based Transient Overvoltage Recognition System
8.7 Data Preprocessing
8.8 Parameter Selection and Optimization
8.9 Extraction and Modification of Field Waveform Parameters
Bibliography
Index
End User License Agreement
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Guide
Cover
Table of Contents
Preface
Begin Reading
List of Illustrations
Chapter 1: Overvoltage Mechanisms in Power Systems
Figure 1.1 Equivalent circuit of a differential-length line segment.
Figure 1.2 Equivalent circuit of a simplified lossless single conductor line of a differential length.
Figure 1.3 Refraction and reflection of travelling waves at point A .
Figure 1.4 Peterson principle.
Figure 1.5 Peterson equivalent circuit in the current source form.
Figure 1.6 Peterson equivalent circuit for calculating refraction voltage.
Figure 1.7 Travelling wave passing through an series inductor.
Figure 1.8 Travelling wave passing through a parallel capacitor.
Figure 1.9 Travelling wave attenuated and distorted by corona.
Figure 1.10 Multiple refraction and reflection of travelling waves.
Figure 1.11 Diagram of uB waveforms under different wave impedance combinations.
Figure 1.12 Bergeron equivalent circuit of a lossless single-conductor line.
Figure 1.13 Bergeron equivalent circuit of a lumped parameter inductor.
Figure 1.14 Bergeron equivalent circuit of a lumped parameter capacitor.
Figure 1.15 Bergeron equivalent circuit of a lumped parameter resistor.
Figure 1.16 Overvoltage classification.
Figure 1.17 Waveforms of the full and chopped standard lightning impulse voltage.
Figure 1.18 Lightning discharge development and the lightning current waveform.
Figure 1.19 Equivalent lightning current waveforms for calculation purposes.
Figure 1.20 Schematic of the generation of induced overvoltages.
Figure 1.21 Induced lightning overvoltages.
Figure 1.23 Three-phase current waves under shielding failures.
Figure 1.24 Schematic diagram of lightning strike spots.
Figure 1.25 Equivalent circuit of lightning striking the line tower.
Figure 1.26 Lightning striking the ground wire at midspan.
Figure 1.27 Equivalent circuit of closing unloaded lines.
Figure 1.28 Schematic of closing probability calculation.
Figure 1.29 The probability curve of the closing overvoltage.
Figure 1.30 Schematic diagram of automatic reclosing.
Figure 1.31 Measured leakage curve of residual voltage on 110–220 kV lines.
Figure 1.32 Equivalent circuit of switching off unloaded lines.
Figure 1.33 Development process of the overvoltage caused by de-energizing unloaded lines.
Figure 1.34 Equivalent circuit and the oscillation wave during arc reignition.
Figure 1.35 Equivalent circuit of disconnecting unloaded transformers.
Figure 1.36 Overvoltages caused by disconnecting unloaded transformers.
Figure 1.37 Circuit and vector diagrams for single-phase grounding.
Figure 1.38 Arc grounding overvoltage caused by arc-quenching at the instant of zero-crossing of the power frequency current.
Figure 1.39 Schematic of splitting overvoltages due to supply out of step.
Figure 1.40 Schematic of overvoltages caused by clearing grounding faults.
Figure 1.41 Schematic of overvoltages due to fault clearing in series compensating systems.
Figure 1.42 Equivalent circuit.
Figure 1.43 Vector diagram.
Figure 1.44 π-type equivalent circuit.
Figure 1.45 Voltage distribution over the unloaded line.
Figure 1.46 Parallel reactor connected at the receiving end of the line.
Figure 1.47 Complex sequence network of single-phase grounding.
Figure 1.48 Wiring of single-phase grounding.
Figure 1.49 Power frequency voltage rise of phase B when R 1 /X 1 = 0
Figure 1.50 Power frequency voltage rise of phase C when R 1 /X 1 = 0.
Figure 1.51 Series linear resonance circuit.
Figure 1.52 Series ferro-resonance circuit.
Figure 1.53 Volt-ampere characteristic of the series ferro-resonance circuit.
Figure 1.54 Wave shapes of ferro-resonance.
Figure 1.55 Boundary curve of self-excitation (I: synchronous zone of self-excitation II: asynchronous zone of self-excitation).
Chapter 2: Transducers for Online Overvoltage Monitoring
Figure 2.1 Installation scheme of transducers.
Figure 2.2 Schematic of a voltage transducer at the bushing tap.
Figure 2.3 Transducer structure.
Figure 2.4 Typical varistor volt–ampere characteristic.
Figure 2.5 Circuit model of the entire system.
Figure 2.6 Wire connection for the impulse response test.
Figure 2.7 Waveforms of the lightning impulse voltage test. (a) Waveform of the lightning impulse voltage test (b) Waveform measured by the transducer.
Figure 2.8 Waveforms of the switching impulse voltage test. (a) Waveform of switching impulse voltage test (b) Waveform measured by the transducer.
Figure 2.9 Sampling structure of arrester valve plates. (R mo ,x – resistance related to the voltage in the unit x ; C mo ,x – capacitance of the unit x; C e ,x – stray capacitance to ground of the node x ; n – number of units) (a) Multi-stage equivalent circuit of arrestors (b) Voltage transducer structure.
Figure 2.10 Equivalent circuit of the conducting properties of ZnO micro-unit.
Figure 2.11 Equivalent circuit for small current range.
Figure 2.12 Equivalent circuit for large current range.
Figure 2.13 Current simulation result.
Figure 2.14 Voltage simulation result.
Figure 2.15 Test principles.
Figure 2.16 Waveforms in laboratory tests.
Figure 2.17 The waveforms on the wave recording panel.
Figure 2.18 The waveforms acquired from the arrester voltage transducer.
Figure 2.19 Operating principles of the overvoltage transducer.
Figure 2.20 Schematic of the shielding enclosure (1 – metal induction plate, 2 – shielding shell, 3 – insulation guardrail, 4 – voltage-dividing unit, 5 – coaxial cable)
Figure 2.21 Photo of the overvoltage transducer.
Figure 2.22 Structure of the transducer shell.
Figure 2.23 Influence of the shielding shell on transducer measurements.
Figure 2.24 Model for capacitance calculation.
Figure 2.25 Ansoft simulation model.
Figure 2.26 Details of the Ansoft model.
Figure 2.27 Schematic of voltage distribution.
Figure 2.28 Comparison of capacitances acquired by different means.
Figure 2.29 Curve of capacitance variation with the conductor length.
Figure 2.30 Schematic of experiment wiring.
Figure 2.31 Waveforms in the power frequency voltage experiment.
Figure 2.32 Schematic of load impedances in the measuring systems.
Figure 2.33 Linear characteristics of the transducer in power frequency voltage test.
Figure 2.34 Waveforms of the lightning overvoltage experiment.
Figure 2.35 Detailed views of the wave fronts in lightning impulse tests.
Figure 2.37 Schematic diagram of longitudinal modulated OVT.
Figure 2.36 Schematic of a BGO Crystal.
Figure 2.38 Schematic diagram of a transverse modulated OVT.
Chapter 3: Online Overvoltage Monitoring System
Figure 3.1 Online overvoltage monitoring system.
Figure 3.2 Overvoltage monitoring system.
Figure 3.3 Screenshot of a line closing overvoltage.
Figure 3.4 Localized amplification of the transient overvoltage signals.
Figure 3.5 Localized amplification of the transient overvoltage signals.
Figure 3.6 Structural diagram of the distributed online overvoltage monitoring system.
Figure 3.7 Framework of the centralized online overvoltage monitoring system.
Figure 3.8 Schematic diagram of the signal conditioning circuit.
Figure 3.9 Schematic diagram of the trigger circuit.
Figure 3.10 Schematic diagram of the control circuit in the protection unit.
Figure 3.11 The structure framework of the data acquisition card.
Figure 3.12 Schematic diagram of A/D conversion.
Figure 3.13 Schematic of pre-trigger.
Figure 3.14 Schematic diagram of variable frequency sampling.
Figure 3.15 Overvoltage monitoring system based on internal networks.
Figure 3.16 General structure of the GPRS-based and Internet-based transmission systems.
Figure 3.17 Comparison between the traditional IP access modes and CE.
Figure 3.18 Issues of photoelectric mixed access.
Figure 3.19 Direct-driven optical fiber mode.
Figure 3.20 Descriptions of the analysis software functions.
Figure 3.21 Main interface of the overvoltage waveform analysis software.
Figure 3.22 Condition monitoring and fault analysis system for transmission lines.
Figure 3.23 Waveforms in real-time monitoring.
Figure 3.24 Fault logging and fault waveform recording.
Figure 3.25 Three-phase waveform display of lightning overvoltages.
Figure 3.26 An enlarged view of the three-phase waveforms of lightning overvoltages at point a.
Figure 3.27 An enlarged view of three-phase waveforms of lightning overvoltages at point b.
Figure 3.28 Waveforms of the direct lightning overvoltage.
Figure 3.29 Waveforms of induced lightning overvoltages.
Figure 3.30 Waveforms of overvoltages on some line at instant 1. Peak: Phase A −847.69 kV, Phase B, −1147.8 kV, Phase C, 1008.9 kV.
Figure 3.34 Waveforms of overvoltages on some line at instant 4. Peak: Phase A −596.51 kV, Phase B, 786.63 kV, Phase C −645.11 kV.
Figure 3.35 Power frequency overvoltage waveforms.
Figure 3.36 An enlarged view of the power frequency overvoltage waveforms.
Figure 3.37 Amplitude–frequency characteristics.
Figure 3.38 Monitoring the secondary voltage of a PT on the 35 kV bus.
Figure 3.39 Waveforms of PT fundamental resonance.
Figure 3.40 Attenuation of PT fundamental resonance.
Figure 3.41 Waveforms of PT resonance of fractional frequency.
Figure 3.42 Attenuation of PT fundamental resonance.
Figure 3.43 Waveforms at the closing of PT in a substation.
Figure 3.44 Spectrum curve of fractional frequency resonance.
Figure 3.45 Resonance overvoltage waveforms.
Figure 3.46 Harmonic analysis diagram (phase A).
Figure 3.47 Waveforms of switching overvoltages.
Figure 3.48 Waveforms of resonance overvoltages.
Figure 3.49 Waveforms of the single-phase grounding overvoltage.
Figure 3.50 Waveforms of the two-phase grounding overvoltage.
Figure 3.51 Intermittent arc grounding overvoltages.
Figure 3.52 Amplified waveform (phase A).
Figure 3.53 Amplified waveform (phase B).
Figure 3.54 Amplified waveform (phase C).
Figure 3.55 Onsite arrangement of the sensor.
Figure 3.56 Sensor outputs upon closing the switch.
Figure 3.57 Waveforms after background noise treatment.
Figure 3.58 Three-phase sensor outputs after subtracting the background noise.
Figure 3.59 Three phase measurements by the sensor with saltation.
Figure 3.60 Decoupled output of the three-phase sensor.
Figure 3.61 Equivalent circuit of the switching process.
Figure 3.62 Rising edges of the sensor output waveform.
Figure 3.63 Decoupled output waveforms of the three-phase sensor.
Figure 3.64 Onsite arrangement of transient monitoring devices installed at high potentials.
Figure 3.65 Transient voltage waveforms during the connecting of an unloaded line with a 220 kV bus via a breaker.
Chapter 4: Wave Process of Incoming Surges and Transient Response Characteristics
Figure 4.1 Parallel multi-conductor (number n ) system.
Figure 4.2 A parallel two-conductor system. Note: Conductor 1 is hit by lightning and Conductor 2 is insulated against the ground.
Figure 4.3 Equivalent circuit of distributed parameter lossy lines.
Figure 4.4 Simplified representation of the single-phase winding.
Figure 4.5 Equivalent circuit of the winding at time instant t = 0.
Figure 4.6 Initial voltage distribution over the winding with different αl values.
Figure 4.7 Voltage distribution in the initial, steady-state and oscillating stages.
Figure 4.8 Voltage distribution of the wave entering a single phase of wye-connected windings (1: Initial voltage distribution; 2: Steady-state voltage distribution; 3: Envelope curve of the maximum voltage).
Figure 4.9 Voltage distribution when waves enter the single phase and three phases of delta-connected windings.
Figure 4.10 Electrostatic coupling between windings.
Figure 4.11 Formation of lightning overvoltage waves on electrical equipment.
Figure 4.12 Four types of initial lightning impulse waves on conductors.
Figure 4.13 Refraction and reflection of overvoltage travelling waves in substations.
Figure 4.14 Electrical composition of a 500 kV substation.
Figure 4.15 ATP-based simulation model of a 500 kV substation.
Figure 4.16 Multi-wave impedance model of a 500 kV ac tower of type 5D1X1-ZH1.
Figure 4.17 ATP-based simulation model of a substation subject to incoming surges.
Figure 4.18 Causes of lightning overvoltage generation.
Figure 4.19 Currents flowing through the tower insulator string.
Figure 4.20 Shapes of travelling voltage and current waves on conductors 400 m from the strike site (shielding failure without flashover).
Figure 4.21 Currents flowing through the tower insulator string.
Figure 4.22 Shapes of the travelling voltage and current waves on conductors 400 m from the strike site (shielding failure with flashover).
Figure 4.23 Currents flowing through the tower insulator string.
Figure 4.24 Shapes of travelling voltage and current waves on the conductor 400 m from the strike site (back flashover without flashover of the insulator string).
Figure 4.25 Currents flowing through the tower insulator string.
Figure 4.26 Shapes of travelling voltage and current waves on the conductor 400 m from the strike site (back flashover with insulator string flashover generated).
Figure 4.27 Along-the-line voltages under shielding failures without flashover.
Figure 4.28 Along-the-line voltages under shielding failures with flashover.
Figure 4.29 Simulation model of a substation.
Figure 4.30 Calculation results of the PT's influences on incoming surges.
Figure 4.31 Typical U–I characteristic curve of a ZnO arrester on the bus of a 500 kV substation.
Figure 4.32 The simulation model of a substation with consideration of arresters.
Figure 4.33 Calculation results (Phase A) of waves without and with consideration of arresters.
Figure 4.34 Arrester current (phase A).
Figure 4.35 Bus voltages with and without consideration of arresters.
Figure 4.36 Waveforms of the incoming surges under near-zone shielding failures with flashover.
Figure 4.37 Waveforms of incoming surges under near-zone shielding failures without flashover.
Figure 4.38 Waveforms of incoming surges under far-zone shielding failures without flashover.
Figure 4.39 Waveforms of incoming surges under far-zone shielding failures with flashover.
Figure 4.40 Scheme of measuring the response characteristics of the lightning overvoltage propagating in the grid.
Figure 4.41 Connection diagram of the HV winding of a 350 MVA/110 kV transformer (phase A).
Figure 4.42 The orientation method.
Figure 4.43 Principle of the time-difference method.
Figure 4.44 Schematic diagram of the TOA method.
Figure 4.45 Peak value of the lightning current.
Figure 4.46 System flow chart.
Figure 4.47 LLS system structure.
Figure 4.48 Location map.
Figure 4.49 A close-up of the discharge traces of Insulator #123 of the faulty line.
Chapter 5: Typical Field Tests and Waveform Analysis in UHVDC Transmission Systems
Figure 5.1 Wiring diagram for sampling overvoltages at the terminals of the arrester counter.
Figure 5.2 Wiring diagram of overvoltage sampling from the converter transformer bushing tap.
Figure 5.3 Arrangement plan for non-contact passive optical fiber overvoltage tests.
Figure 5.4 Connection diagram of the overvoltage tests for DC filters.
Figure 5.5 Overvoltage waveforms when disconnecting the convertor transformer (first time).
Figure 5.6 Overvoltage waveforms when disconnecting the convertor transformer (second time).
Figure 5.7 Overvoltage waveforms when disconnecting the convertor transformer (third time).
Figure 5.8 Overvoltage waveforms when connecting the convertor transformer (first time).
Figure 5.9 Overvoltage waveforms when connecting the convertor transformer (second time).
Figure 5.10 Measured waveforms during the deblocking of the inverter at the low-voltage terminal.
Figure 5.11 Measured waveforms during emergency switch-off of pole I.
Figure 5.12 Transient grounding fault test of the ac line (sampled from the resistor).
Figure 5.13 Transient grounding fault test of the ac line (sampled from the capacitor).
Figure 5.14 Fault test for the DC line (pole I, near station A).
Figure 5.15 Fault test for the DC line (Pole II, near Station A).
Figure 5.16 Fault test for the DC line (pole II).
Figure 5.17 Fault test for the ac line at the converter side (sampled from the dc filter).
Figure 5.18 Fault test for the dc line (forward power transmission, near station B, pole I).
Figure 5.19 Monopolar power mode.
Figure 5.20 Bipolar power mode.
Figure 5.21 Metallic return of pole II.
Figure 5.22 Disturbance fault test for the dc line (near station A, pole II).
Figure 5.23 Instantaneous grounding fault test for the ac line (phase C).
Chapter 6: Overvoltage Digital Simulation
Figure 6.1 Dialog box for parameters of the LCC model for 500 kV overhead transmission lines.
Figure 6.2 line-side three-phase voltages at the opening of a 500 kV unloaded line.
Figure 6.3 Dialog box of parameter setting for disconnecting unloaded transformers.
Figure 6.4 Simulated system for disconnecting transformers.
Figure 6.5 waveforms of the high-voltage bus during the disconnection of the transformer.
Figure 6.6 Three-phase waveforms of the flux linkage.
Figure 6.7 line-side three-phase voltages at the closing of a 500 kV unloaded transmission line.
Figure 6.8 Phase A voltage at the line end when closing a 500 kV unloaded transmission line.
Figure 6.9 Line-side three-phase voltages after closing a 500 kV unloaded transmission line with a closing resistor installed.
Figure 6.10 Phase A voltage at the line end when closing a 500 kV unloaded transmission line with a closing resistor installed.
Figure 6.11 Cable model.
Figure 6.12 Simulation model for line closing.
Figure 6.14 Field measured waveforms of the overvoltage caused by closing lines.
Figure 6.13 Simulated waveforms of the overvoltage due to closing lines.
Figure 6.15 Simulation model for automatic reclosing.
Figure 6.16 Waveforms when protection is actuated.
Figure 6.17 Waveforms at single-phase reclosing.
Figure 6.18 Waveforms at three-phase reclosing.
Figure 6.19 Initial connection diagram.
Figure 6.20 Disconnection of main transformer 2 from Bus II.
Figure 6.21 Overvoltage waveforms when switching breakers of main transformer 2.
Figure 6.22 Simulation program of the bus.
Figure 6.23 Simulated waveforms when switching the breakers of main transformer 2.
Figure 6.24 Line-side three-phase voltage after closing unloaded transformers.
Figure 6.25 Waveforms of the three-phase line-side inrush current after closing unloaded transformers.
Figure 6.26 Model for overvoltages due to closing capacitors.
Figure 6.27 Waveforms of the 6.3 kV bus voltage when switching on the capacitor.
Figure 6.28 Diagram of unloaded undamaged wire.
Figure 6.29 Curve of voltage variation with the conductor length.
Figure 6.30 Circuit model.
Figure 6.31 Parameter settings.
Figure 6.32 Simulated waveforms of the line voltage.
Figure 6.33 Model for single-phase grounding faults.
Figure 6.34 Waveforms of phase-to-ground voltages of non-fault phases in the case of single-phase grounding.
Figure 6.35 Waveform of non-fault phase voltage in the case of two-phase grounding.
Figure 6.36 Simulation model for short-circuit faults in a substation.
Figure 6.37 Voltage waveforms in the case of grounding faults.
Figure 6.38 Current waveforms in the case of grounding faults.
Figure 6.39 A typical lightning current wave.
Figure 6.40 Equivalent circuit of lightning discharge.
Figure 6.41 Single-line diagram for a substation.
Figure 6.42 Simulated lightning waveform.
Figure 6.43 Parameter setting for overhead lines.
Figure 6.44 Mod file edit page.
Figure 6.45 Arrester characteristic data.
Figure 6.46 Arrester volt–ampere characteristic curve.
Figure 6.47 Circuit model.
Figure 6.48 Voltage waveforms of the three-phase conductors of tower #4.
Figure 6.49 Overvoltage waveforms of three-phase conductors of line 1.
Figure 6.50 Overvoltage waveforms of three-phase conductors at the place where instrument transformers are installed.
Figure 6.51 Overvoltage waveforms at three-phase leads of the transformer.
Figure 6.52 Substation structure diagram.
Figure 6.53 Relations between ϕ (t ) and i (t ).
Figure 6.54 Excitation curve of an 110 kV PT (Phase C).
Figure 6.55 Equivalent principle of single-phase three-winding transformers.
Figure 6.56 Single-phase three-winding PT model in ATP.
Figure 6.57 Three-phase PT connection diagram.
Figure 6.58 Saturable transformer model.
Figure 6.59 PT resonance at the 35 kV side.
Figure 6.60 Main connection of the ac side of a converter station.
Figure 6.61 Equipment state diagram after energizing a line.
Figure 6.62 Simulation model for closing GIS breakers.
Figure 6.63 VFTO on the bus (phase A).
Figure 6.64 Bus voltage waveform when the GIS is actuated.
Figure 6.65 Bus VFTO waveform when the GIS is actuated.
Figure 6.66 composition of HVDC transmission systems.
Figure 6.67 Converter valve model.
Figure 6.68 PSCAD converter valve model.
Figure 6.69 Converter transformer model in PSCAD.
Figure 6.70 Parameter setting details for converter transformers.
Figure 6.71 Steps to model lines in PSCAD.
Figure 6.72 Modeling step 1.
Figure 6.73 Tower parameter settings.
Figure 6.74 Behind source impedance mode.
Figure 6.75 At the Terminal mode.
Figure 6.76 Power control mode.
Figure 6.77 DC filter types.
Figure 6.78 AC-side filter types.
Figure 6.79 Rectifier-side control mode.
Figure 6.80 Inverter side control mode.
Figure 6.81 PSCAD model for UHVDC systems.
Figure 6.84 DC-side filtering equipment.
Figure 6.85 Current waveform at the high-voltage terminal of pole II at the inverter side.
Figure 6.86 Voltage waveform at the high-voltage terminal of pole II at the inverter side.
Chapter 7: Entity Dynamic Simulation of Overvoltages
Figure 7.1 Model for lightning direct striking channel of a 200 km overhead transmission line.
Figure 7.2 Self-impedance of each line and the mutual impedance between each line and ground wire #1.
Figure 7.3 Wire-to-ground admittance of ground wire #1 and the mutual admittance between each line and ground wire #1.
Figure 7.4 Circuit model for self-impedances and mutual impedances.
Figure 7.5 Vertical cylinder model for the tower.
Figure 7.7 Model for the tower and ground connector.
Figure 7.8 Insulator model.
Figure 7.9 Circuit structural diagram of a transmission line unit model when lightning directly hits the tower top.
Figure 7.10 Circuit structural diagram of a transmission line unit model when shielding failure occurs.
Figure 7.11 Diagram of the simulated tower (when the lightning is 60 km away from substation 1).
Figure 7.12 Voltage of each point on the line.
Figure 7.15 Currents of ground wire branches.
Figure 7.13 voltage of each ground wire point.
Figure 7.16 Voltages at the strike point under different lightning current amplitudes.
Figure 7.17 Lightning waveforms reaching the substation with different strike spots.
Figure 7.18 Lightning waveform reaching substations with smaller grounding resistance.
Figure 7.19 Dynamic simulation system for lightning electromagnetic transients on transmission lines.
Figure 7.20 Schematic diagram of the channel of lightning directly striking the tower.
Figure 7.21 Schematic of the lightning channel in the case of shielding failures.
Figure 7.22 Diagram of installation sites of current transducer models.
Figure 7.23 Diagram of installation sites for PT models.
Chapter 8: Overvoltage Pattern Recognition in Power Systems
Figure 8.1 Overvoltage classification adopted in this book.
Figure 8.2 Wavelet decomposition process.
Figure 8.3 Wavelet decomposition results.
Figure 8.4 Singular value decomposition of lightning overvoltages.
Figure 8.6 Singular value decomposition of high-frequency resonance overvoltages.
Figure 8.7 Structure of sorter 1.
Figure 8.8 Structure of sorter 2.1.
Figure 8.9 Structure of sorters 2.2 and 3.
Figure 8.10 Schematic of the SVM Structure.
Figure 8.11 Results of PCA dimension reduction.
Figure 8.12 Results of the CV method.
Figure 8.13 Basic steps of the genetic algorithm.
Figure 8.14 GA results.
Figure 8.15 Basic process of the PSO algorithm.
Figure 8.16 PSO algorithm for parameter optimization.
List of Tables
Chapter 2: Transducers for Online Overvoltage Monitoring
Table 2.1 Comparison of capacitances acquired by different methods
Table 2.2 Selection of parameters of the transducer and capacitance
Table 2.3 Data measured by the voltage transducer in an ac power frequency experiment
Table 2.4 Performance parameters of typical Pockels electro-optical crystals
Table 2.5 General Properties of BGO
Table 2.6 Advantages and disadvantages of longitudinal and transverse electro-optical modulation
Chapter 3: Online Overvoltage Monitoring System
Table 3.1 Bandwidth requirements for several typical applications
Table 3.2 Start\stop monitoring
Table 3.6 File downloads
Table 3.7 Comparison between CE and other access modes
Table 3.8 Supporting rates (Gbps) under different modes and channel numbers
Table 3.9 Statistics of switching overvoltages from May 2015 to July 2015
Table 3.10 Statistics of the resonance overvoltages from May 2015 to July 2015
Table 3.11 Impact coefficients of phase-to-ground overvoltages in some substation
Table 3.12 Characteristic values
Table 3.13 List of the overvoltage waveform parameters
Table 3.14 List of the switching overvoltage waveform parameters
Chapter 4: Wave Process of Incoming Surges and Transient Response Characteristics
Table 4.1 Correction Table of the coupling coefficient k 1.
Table 4.2 Transformer entrance capacitances
Table 4.3 Parameters of the arrester V–I characteristic curve
Table 4.4 Insulation levels of transformers rated 110 kV and 220 kV in different countries
Table 4.5 Comparison between 1.2/50 µs and 2.4/50 µs
Table 4.6 Transposition coefficients at the zero point of the chopped waves 0.3 and 0.4
Table 4.7 Preliminary discharge time of the chopped impulse waves 2.5 and 5.0
Chapter 6: Overvoltage Digital Simulation
Table 6.1
Table 6.2 Conversion data A for the PT excitation curve of an 110 kV bus
Table 6.3 Conversion data B for the PT excitation curve of an 110 kV bus
Table 6.4 Parameters of the transformer three-phase windings
Table 6.5 ATP transformer model parameters
Table 6.6 Measured data of an 110 kV bus
Table 6.7 Substation bus parameters
Table 6.8 Equivalent models and parameters for GIS components
Table 6.9 AC system data in UHVDC systems
Chapter 8: Overvoltage Pattern Recognition in Power Systems
Table 8.1 Range of each frequency band
Table 8.2 Characteristic values within each frequency range
Table 8.3 Comparison of accuracy under different normalization approaches
Table 8.4 Parameter selection and accuracy of each level of sorter
Measurement and Analysis of Overvoltages in Power Systems
Jianming Li
Sichuan Electric Power Research Institute (SEPRI)
State Grid Corporation of China (SGCC)
Sichuan, China
This edition first published 2018
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Library of Congress Cataloging-in-Publication Data
Names: Li, Jianming, 1952- author.
Title: Measurement and analysis of overvoltages in power systems / by Jianming Li.
Description: Singapore ; Hoboken, NJ : John Wiley & Sons, 2018. | Includes bibliographical references and index. |
Identifiers: LCCN 2017041391 (print) | LCCN 2017055744 (ebook) | ISBN 9781119129059 (pdf) | ISBN 9781119129042 (epub) | ISBN 9781119128991 (cloth)
Subjects: LCSH: Overvoltage.
Classification: LCC TK7870 (ebook) | LCC TK7870 .L4825 2018 (print) | DDC 621.31/7-dc23
LC record available at https://lccn.loc.gov/2017041391
Cover design by Wiley
Cover image: © Pobytov/Gettyimages
With the rapid development of computer technology and power electronic technology, the methods of measuring and analyzing overvoltages in power systems have changed significantly. In this book, by adopting digital simulation and entity dynamic simulation and by using a substantial amount of field-measured data, overvoltage parameters are extracted and overvoltage patterns recognized. The new concepts and methods of overvoltage measurement in this book can be used to instruct companies and organizations about monitoring, recording and analyzing overvoltages so as to ensure secured operation of the power system.
The book consists of eight chapters: Chapter 1 briefly introduces the overvoltage mechanism; Chapter 2 relates to the acquisition system of overvoltage monitoring devices; Chapter 3 deals with the transmission and recording system of overvoltage monitoring devices; Chapter 4 studies the transient response of lightning waves; Chapter 5 is concerned with typical field tests and waveform analysis for the UHVDC transmission system; Chapter 6 is mainly about digital simulation; Chapter 7 relates to entity dynamic simulation for overvoltages on transmission lines; and Chapter 8 provides details on overvoltage pattern recognition. I am the chief editor of the book, but experiments involved in this book, together with compilation and proofreading were conducted cooperatively by Chen Shaoqing, Zhang Yu, He Xiangyu, Xu Wen, Qin Dahai, Ren Xiaohua, Bi Yanqiu, Jiang Yuhan, Xie Shijun, Li Shuqi, Ouyang Renle, Li Guoyi, Huang Yidan, Zhang Luo, Liu Yuqing, Chen Xin, Li Hewei, Zhou Yue, Yang Hailong and Luo Yiqiao.
My heartfelt appreciation also goes to Professor Zeng Rong from Tsinghua University, Professor Yang Qing from Chongqing University and Senior Engineer Cao Yongxing from Sichuan Electric Power Research Institute, State Grid Corporation of China. All of them have provided a considerable amount of valuable advice related to the manuscript.
Errors and deficiencies may be found in the book due to my limited ability. Advice and criticism are welcome!
Jianming Li
April 2017