Study of Distributed Grounding Line Selection Application Based on GOOSE

This paper proposes a method of intelligent protection and location integration for single-phase grounding fault in small current grounding system, which can quickly transfer the grounding current at the grounding fault point and make the current at the grounding fault point tend to zero. The arc cannot maintain and extinguish, thereby protecting the personal safety of the staff. At the same time, the fault location is carried out according to the principle that the zero sequence electrical parameters on different lines and the zero sequence electrical parameters of each line after the active grounding of the fault phase bus before and after the single-phase grounding fault. Finally, through PSCAD/EMTDC and Matlab simulation, the feasibility and effectiveness of this method are verified from different ground resistance, initial phase angle, and fault distance in small current grounding system.

Transient analysis is carried out for the single-phase grounding fault in small current grounding system, the transient grounding current expression is derived, and the influence factors are analyzed. Introduces a method for non-stationary and non-linear signal analysis method-Hilbert Huang transform (HHT) to analyze the single phase grounding fault in small current grounding system, HHT can be better used to extract the abundant transient time frequency information from the non-stationary and nonlinear fault current signals. The empirical mode decomposition (EMD) process and the normalized Hilbert Huang transform (NHHT) algorithm are presented, NHHT is used to analyze and verify an example of the nonlinear and non-stationary amplitude modulation signals. Build a small current grounding system in the EMTP_ATP environment, by selecting the appropriate time window to extract the transient signals, NHHT is used to analyze the transient current signals, and the Hilbert amplitude spectrum and the Hilbert marginal spectrum of the zero sequence transient current signals are obtained.

This paper investigates fault line selection in small current grounding systems, focusing on the zero sequence current phase characteristics. Small current grounding systems, prevalent in medium voltage distribution networks, face challenges in fault detection due to minimal fault currents during single status phase grounding faults. Traditional methods relying on manual line switching and zero sequence voltage monitoring are inefficient and can induce overvoltage. This study categorizes fault line selection techniques into three approaches: steady-state fault information, transient information, and modern signal processing technology. The analysis of zero sequence currents in non-grounded systems reveals that fault line zero sequence currents equal the sum of system capacitive currents, flowing opposite to those in non-fault lines. Additionally, transient signal analysis shows that these signals provide more robust information for fault detection. MATLAB simulations validate the theoretical models, demonstrating that zero sequence current direction and amplitude effectively identify fault lines. The results confirm the efficacy of combining steady-state and transient signal analyses for accurate fault line selection, contributing to enhanced safety and reliability in power distribution networks. This research offers practical insights and tools for engineers, improving fault management and reducing potential economic losses in small current grounding systems.

In order to improve the line selection accuracy of the fault line selection device for small current grounding systems, a line selection method based on information fusion is proposed, that is, several complementary single line selection methods based on transient and steady state characteristics are used for comprehensive line selection. Firstly, wavelet method, zero-sequence active component method, and fifth harmonic method are used according to the characteristic definition of transient and steady-state fault characteristics, and then the rough set theory algorithm model is used to fuse the faults with various fault characteristics to select the fault line. In Matlab, a distribution network model was built and a program of fusion algorithm was written for simulation analysis and verification of route selection methods. The simulation results show that the line selection method based on rough set theory and information fusion has high accuracy and good application value.

Based on the detailed analysis of single-phase grounding fault characteristics in the small current grounding system, an adaptive multi-criteria fusion method of fault-line selection based on transient signal is proposed in this paper. This method introduces fault membership and criterion confidence to achieve the fusion of multiple fault-line selection criteria. At the same time, each criterion adaptively determines whether to participate in the selection according to its confidence level. MATLAB/Simulink simulation results indicate that this fault-line selection method is not influenced by such factors as the transient characteristics of the fault, fault resistance, length of the faulty line, etc.

The probability of two-point same-phase ground fault (TPSPGF) is low in small current grounding system (SCGS), but the harm of TPSPGF can not be ignored. However, there is no effective fault line selection method for TPSFGF at present. A fault line selection scheme for TPSPGF is proposed in this paper. Firstly, the simplified equivalent circuit model of TPSPGF in SCGS is established, and the steady and transient fault characteristics of TPSPGF are analyzed. Secondly, two common line selection methods for single point ground fault are introduced, and their applicability for TPSPGF is analyzed. Finally, based on the fault component of phase current, the line selection procedure for TPSPGF is given. The correctness of the analysis results and the effectiveness of selection scheme is verified by simulation.

Small current grounding system is mainly used in China’s distribution network. When single-phase grounding fault occurs in the distribution network, it is important to quickly and accurately select the fault line and locate the fault section to ensure the safe and stable operation of the system. In this paper, the fault location methods for the small current grounding system are described in detail, the advantages and disadvantages of various methods are compared, the main problems existing in the low-current grounding system are pointed out, and the future development direction is prospected.

On the basis of analysis on the characteristics of single phase grounding fault occurred in small current neutral grounding system, a fault location method using Learn Vector Quantization Neural Network is put forward. Combined LVQ Neural Network with C-type of traveling wave location method, the purpose of precise location can be achieved. The simulation results of ATP-EMTP and MATLAB show that the LVQ Neural Network can determine fault location quite effectively and rapidly.

单端行波故障定位法以定位速度快，无需巡线，成本低，可以进行多次定位等优点，成为小电流接地系统中单相接地故障定位的有效方法之一。但是其定位精度容易受到多种因素的影响，尤其是受到行波的波速精度的影响，在行波理论的基础上提出一种不受行波波速影响的单端行波故障定位算法，理论推导结果表明，这种算法正确可靠。仿真结果表明，这种定位算法的精度优于传统的单端定位方法。 The single-port wavelet fault location has the merits that location speed is fast, it is not need inspect lines, low cost and may locate many times, so it is one of the effective methods of single-phase grounding fault location of small current grounding system. But its location precision is influenced by many factors, especially the speed precision of the wavelet. On the basis of wavelet theory, it proposes a new arithmetic of single-port wavelet fault location for small current grounding system which not influenced by the speed of wavelet. The result shows that the arithmetic is correct and the simulation result shows that the precision of this arithmetic is better than the traditional single-port wavelet fault location method.

Single phase grounding fault is the most common fault in distribution system. It mostly occurs in wet and rainy weather, which is caused by many factors, such as tree barrier, single-phase breakdown of distribution line insulator, single-phase disconnection, small animal harm and so on. Single phase grounding not only affects the normal power supply of users, but also may produce overvoltage, burn equipment, and even cause phase to phase short circuit, expanding the scope of accidents. The 10-35kV lines in China’s urban power grid are mainly neutral non effective grounding systems. After the occurrence of single-phase grounding fault, the fault characteristic signal is weak and difficult to extract, resulting in the difficulty of accurate fault diagnosis. However, due to the limitations of the traditional fault diagnosis principle relying on the zero sequence voltage and current criterion, there are serious misjudgments and omissions in the single-phase grounding fault diagnosis of distribution network. With the rapid development of distribution network in recent years, the functions of wave recording and event playback of distribution automation system and its equipment can collect online power grid operation information before and after. After the accident, a sample database of accident cases shall be formed. How to use these data to improve the

A large number of distributed generators access to low resistance grounding system may have great influence on the fault characteristics of single phase ground. In view of low resistance ground active distribution network, the connection mode of Inverter-interfaced Distributed Generators (IIDG) is discussed comprehensively based on operation safety and protection requirements. The equivalent model of IIDG and simplified zero sequence network model of low resistance grounding system contain multi-IIDG for single phase ground fault are established. The amplitude and phase characteristics of zero sequence current in single phase grounding fault of the system and the characteristics of high-resistance ground fault are analyzed. Simulative results by MATLAB/Simulink verifies the correctness of the analysis results of fault characteristics. The conclusions could be provided as reference for solving the grounding protection of system with high penetration of distributed generator.

When single-phase to ground fault occurs in small current grounding system, the zero-sequence transient current contains a lot of complex fault information. In order to extract characteristic from the zero-sequence current accurately as the criterion of fault line selection, this paper puts forward a method of fault line selection based on VMD energy entropy and optimized K-means clustering. Firstly, the zero-sequence current of each line is decomposed by VMD (variational mode decomposition, VMD), and each sub mode of the original current is obtained. Secondly, the energy entropy of each sub mode is calculated as the characteristic quantity of each line state. Finally, the optimized K-means clustering algorithm is used to cluster the fault feature to realize fault line selection. In this paper, Simulink is used to simulate the single-phase to ground fault in resonant grounded system and the results show that the method that has high accuracy can provide reference for practical engineering application.

At present, the problematic line selection method for single phase grounding faults of the small current grounding system has been mature, but line selection method for two-point same-phase ground faults is rarely studied. For the problem that the accuracy of line selection equipment is low for two-point same-phase ground faults, a fault model is established and the fault signatures are analyzed theoretically. As the faulty line zero-sequence current is affected by more factors, it is not possible to select the line with the common line selection technology for single-phase grounding faults. By further theoretical derivation, a new method for successive judgment of faulty lines is proposed, and the correctness of problematic characteristics and the feasibility of line selection technology are verified to many different cases by simulation using the ATP simulation experimental platform.

When a single-phase-to-ground fault occurs in the distribution network, there is a wealth of information in the transient process of the fault line, from which the fault line selection criterion can be extracted. In this paper, based on the analysis of the related principle of wavelet transform and the concept of entropy, the comprehensive wavelet entropy is defined, and the principle and process of fault line selection are put forward by analyzing the variation coefficients of a group of comprehensive wavelet entropy. Finally, the simulation software is used to verify the fault line selection method under different fault conditions to prove its applicability and feasibility.

The frequent occurrence of single-phase grounding faults affects the reliable operation of power systems. When a single-phase grounding fault occurs, it is difficult to accurately identify the fault type because of the weak characterization and subtle distinction between different fault types. Therefore, this paper proposes a single-phase grounding fault type identification method based on the multi-feature transformation and fusion. Firstly, the Hilbert–Huang transform (HHT) was used to preprocess the fault recorded wave data to highlight the characteristics between different fault types. Secondly, the deep learning model ResNet18 and the long short-term memory (LSTM) are designed to extract the complex abstract features and time-series correlation features from the preprocessed data set separately. Finally, it designs a fusion model to combine the advantages of heterogeneous models to identify the type of single-phase grounding fault. Experiments validate that the method is good at fully mining the characteristics of the fault types contained in the fault recorded wave data, so it can identify multiple types of faults with strong robustness and provide a reliable basis for the subsequent formulation of targeted fault-handling measures.