Hierarchical Protection for Smart Grids

Zengping Wang and Jing Ma, North China Electric Power University, Beijing, China

• About the Author ixForeword xiPreface xiiiIntroduction xv1 Basic Theories of Power System Relay Protection 11.1 Introduction 11.2 Function of Relay Protection 11.3 Basic Requirements of Relay Protection 31.3.1 Reliability 31.3.2 Selectivity 41.3.3 Speed 41.3.4 Sensitivity 51.4 Basic Principles of Relay Protection 61.4.1 Over-Current Protection 61.4.2 Directional Current Protection 61.4.3 Distance Protection 71.5 Hierarchical Relay Protection 91.5.1 Local Area Protection 101.5.2 Substation Area Protection 111.5.3 Wide Area Protection 121.5.4 Constitution Mode of Hierarchical Relay Protection 131.6 Summary 15References 152 Local Area Conventional Protection 172.1 Introduction 172.2 Transformer Protection 182.2.1 Adaptive Scheme of Discrimination between Internal Faults and Inrush Currents of Transformer Using Mathematical Morphology 182.2.2 Algorithm to Discriminate Internal Fault Current and Inrush Current Utilizing Variation Feature of Fundamental Current Amplitude 302.2.3 Identifying Transformer Inrush Current Based on Normalized Grille Curve (NGC) 392.2.4 Adaptive Method to Identify CT Saturation Using Grille Fractal 502.2.5 Algorithm for Discrimination Between Inrush Currents and Internal Faults Based on Equivalent Instantaneous Leakage Inductance 572.2.6 A Two-Terminal Network-Based Method for Discrimination between Internal Faults and Inrush Currents 702.3 Transmission Line Protection 822.3.1 Line Protection Scheme for Single-Phase-to-Ground Faults Based on Voltage Phase Comparison 832.3.2 Adaptive Distance Protection Scheme Based on the Voltage Drop Equation 992.3.3 Location Method for Inter-Line and Grounded Faults of Double-Circuit Transmission Lines Based on Distributed Parameters 1172.3.4 Adaptive Overload Identification Method Based on Complex Phasor Plane 1342.3.5 Novel Fault Phase Selection Scheme Utilizing Fault Phase Selection Factors 1482.4 Summary 172References 1723 Local Area Protection for Renewable Energy 1753.1 Introduction 1753.2 Fault Transient Characteristics of Renewable Energy Sources 1763.2.1 Mathematical Model and LVRT Characteristics of DFIG 1773.2.2 DFIG Fault Transient Characteristics When the Crowbar Protection Is Not Put into Operation 1783.2.3 DFIG Fault Transient Characteristics When the Crowbar Protection Is Put into Operation 2113.3 Local Area Protection for Centralized Renewable Energy 2303.3.1 Connection Form of a Wind Farm and its Protection Configuration 2313.3.2 Adaptive Distance Protection Scheme for Wind Farm Collector Lines 2333.3.3 Differential Protection Scheme for Wind Farm Outgoing Transmission Line 2393.4 Local Area Protection for Distributed Renewable Energy 2483.4.1 Adaptive Protection Approach for Distribution Network Containing Distributed Generation 2483.4.2 Islanding Detection Method 2553.5 Summary 269References 2704 Topology Analysis 2734.1 Introduction 2734.2 Topology Analysis for Inner Substation 2734.2.1 Characteristic Analysis of the Main Electrical Connection 2744.2.2 Topology Analysis Method Based on Main Electrical Wiring Characteristics 2754.2.3 Scheme Verification 2784.3 Topology Analysis for Inter-substation 2844.3.1 Static Topology Analysis for Power Network 2854.3.2 Topology Update for Power Network 2874.3.3 Scheme Verification 2914.4 False Topology Identification 2944.4.1 Road-Loop Equation 2944.4.2 Analysis of the Impacts of Topology Error and Undesirable Data on Branch Current 2964.4.3 Topology Error Identification Method Based on Road-loop Equation 3004.4.4 Scheme Verification 3014.5 Summary 315References 3165 Substation Area Protection 3175.1 Introduction 3175.2 Substation Area Protection Based on Electrical Information 3175.2.1 Substation Area Regionalization 3185.2.2 Typical Fault Cases 3235.2.3 Scheme Performance Analysis 3265.3 Substation Area Protection Based on Operating Signals 3275.3.1 Setting Principle of Adaptive Current Protection 3275.3.2 Supporting Degree Calculation Method 3305.3.3 Substation Area Current Protection Algorithm 3345.3.4 Scheme Verification 3385.4 Summary 346References 3466 Wide Area Protection 3476.1 Introduction 3476.2 Wide Area Protection Using Electrical Information 3476.2.1 Wide-Area Protection Using Fault Power Source Information 3486.2.2 Wide-Area Protection Using Fault Network Information 3586.2.3 Wide-Area Protection Suitable for Multiple Fault Identification 3696.3 Wide Area Protection Using Operating Signals 3756.3.1 Wide-Area Protection Based on Distance Protection Operational Signal 3766.3.2 Wide-Area Protection Based on Current Protection Operational Signal 3936.3.3 Wide-Area Protection Based on Virtual Impedance of Fault Component 4066.4 Wide Area Tripping Strategy 4196.4.1 Tripping Strategy Based on Directional Weighting 4196.4.2 Simulation Verification 4286.5 Summary 432References 433Appendices 435Index 439