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This series of papers report on relay protection strategies that satisfy the demands of a strong smart grid. These strategies include ultra-high-speed transient-based fault discrimination, new co-ordination principles of main and back-up protection to suit the diversification of the power network, optimal co-ordination between relay protection and...
Citations
... Currently, the power system is swiftly evolving towards a large-scale power supply, cross-regional transmission, and high-voltage DC transmission. Consequently, the demands for configured relay protection facilities are progressively becoming more stringent and standardized [1][2][3]. Relay protection in electric power systems generally comprises relay protection devices, current transformers, voltage transformers, and other elements. The relay protection device utilizes collected current and voltage signals to perform logical operations based on preset protection trigger conditions. ...
To ensure a stable and reliable power supply, the valid and timely response of protective relays are indispensable. Through the prevention of fault expansions, potential equipment damage or system collapse can be averted, where their setting is one vital prerequisite for such effective implementations. However, the increasing complexity of distribution power systems results in more challenges for protection tuning strategies. Ergo, this paper presents an ensemble that combines the independent factor evaluation (IFE) and quantum genetic optimization (QGO) models to further optimize the performance of relays according to their distributed tuning environment. In this ensemble, both near and far-end fault characteristics can be incorporated. In the first stage, the IFE dimensional reduction model is deployed for massive heterogeneous input data, where the statistical independence of input signals is calculated, the linear transformation matrix to decouple mixed signals is found, the linear combination of such signals is formed, and the non-Gaussian property to sort them is established. This can ameliorate the following calculation efficiency under those high-dimensional data scenarios. Subsequently, the QGO model is designed to further improve relay settings, where qubit representation is built to reduce required chromosomes, the linear superposition of the optimal solution probability in different states is implemented for a better diversity and convergence performance, and a self-adaption quantum gate is established to dynamically update the qubit chromosome groups and two-state solution combinations. Lastly, an empirical case study is presented, which validates the enhanced convergence, accuracy, and rapidity of the proposed ensemble.
... Currently, electrical and non-electrical protections are used to isolate transformer faults to ensure their safe operation [2,7]. Electrical protection primarily involves forming a differential circuit through the currents on each side of the transformer [8], with protection schemes using current differences in the differential circuit under internal faults, external faults, and normal operation as criteria for action, aimed at protecting against various inter-phase can be controlled by the C51 microcontroller to operate the full bridge inverter across a wide frequency range of 20 kHz to 400 kHz, fully meeting the WPC specification frequency requirement of 100 kHz to 250 kHz. The typical application circuit for the SCT63240 chip can be obtained from its data manual. ...
To ensure stable and normal transformer operation, light gas protection of the transformer Buchholz relay is essential. However, false alarms related to light gas protection are common, and troubleshooting them often requires on-site gas sampling by personnel. During this time, the transformer’s operating state may rapidly deteriorate, posing a safety threat to field staff. To tackle these challenges, this work presents the near-field, thin-sliced transformer monitoring system that uses Electromagnetic Energy Transmission and Wireless Sensing Device (ETWSD). The system leverages external wireless energy input to power gas monitoring sensors. Simultaneously, it employs Near-Field Communication to obtain real-time concentrations of light gases, along with the electrified state and temperature. In field testing conducted on transformer relays’ gas collection chambers, the ETWSD effortlessly monitors parameters within warning ranges, encompassing methane gas concentrations around 1000 ppm, leakage voltage ranging from 0–100 V, and relay working temperatures up to 90 °C. Additionally, to facilitate real-time diagnosis for electrical workers, we have developed an Android-based APP software that displays current light gas concentrations, leakage voltage collection values, and temperature, while also enabling threshold judgment, alarms, and data storage. The developed ETWSD is expected to aid on-site personnel in promptly and accurately evaluating transformer light gas protection error alarm faults. It provides a method for simultaneous, contactless, and rapid monitoring of multiple indicators.
... Self-organizing network wireless communication is a multihop autonomous system consisting of a group of nodes equipped with wireless transceiver devices. It does not rely on preset infrastructure and offers several unique features such as self-healing networking, rapid deployment, absence of a control center, and strong survivability [10][11][12][13]. Selforganizing wireless communication represents a novel wireless network structure that originated from WLAN and Ad-hoc networks. ...
The development of offshore wind power is a crucial step in China’s energy transition and the achievement of carbon peaking and carbon neutrality goals. This paper first introduces a wireless communication technology for independent networking. Its applicability in the field of relay protection is analyzed, and a security encryption scheme for its use in relay protection services is designed. Considering the primary wiring form and protection function configuration of offshore wind power, a multi-terminal wireless differential protection method suitable for offshore wind power collection lines is proposed, achieving synchronization error less than 3° and typical delay of wireless self-organizing network communication less than 12ms. Utilizing multi-terminal data synchronization technology and differential protection algorithms, a scheme for fault isolation and recovery of non-faulty wind turbines is established, thereby achieving minimal range isolation of offshore wind power collection line faults and precise fault section location. The action time of multi-terminal differential protection is less than 40ms. Finally, experimental results confirm that this technology’s various metrics satisfy the demands of engineering applications and hold promotional value, offering a reference for the practical application of wireless communication technology in offshore wind power collection line protection services.
... Relay protection devices are crucial components in power systems, serving the important function of swiftly disconnecting faults and maintaining the stability of the grid [1][2][3]. The reliability of these devices has a direct impact on the overall stability of the grid [4][5][6]. ...
... Matrix Multiply: performing matrix multiplication on the two matrices [3][2] and [2][3]; Management operation: verifying if the entered username and password match the set username and password, and output the result. ...
Traditionally, studies have primarily focused on single event effects in aerospace electronics. However, current research has confirmed that atmospheric neutrons can also induce single event effects in China’s advanced technology relay protection devices. Spallation neutron irradiation tests on a Loongson 2K1000 system-on-chip based relay protection device have revealed soft errors, including abnormal sampling, refusal of operation and interlock in the relay protection device. Given the absence of standardized evaluation methods for single event effects on relay protection devices, the following research emphasizes the use of Monte Carlo simulation and software fault injection. Various types of single event upsets, such as single bit upsets, dual bit upsets, and even eight bit upsets, were observed in Monte Carlo simulations where atmospheric neutrons hit the chip from different directions (top and bottom). The simulation results indicated that the single event effect sensitivity of the relay protection device was similar whether the neutron hit from the top or the bottom. Through software fault injection, the study also identified soft errors caused by neutron induced single event upsets on the Loongson 2K1000 system, including failure to execute, system halt, time out, and error result. And the soft error number of system halts and error results exceeded that of time outs and failures to execute in all three tested programs. This research represents a preliminary assessment of single event effects on relay protection devices and is expected to provide valuable insights for evaluating the reliability of advanced technology relay protection devices.
... Distributed PV power output is closely related to the local real-time solar irradiation intensity, with obvious intermittence and fluctuation. After the large-scale distributed PV is connected to the power grid, the characteristics of the traditional DN have been changed from one-way to two-way power flow network, which has brought many adverse effects on the voltage [1], power quality [2], relay protection [3] and dispatching operation [4,5] of the DN. It seriously threatens the safe and stable operation of DN. ...
With increasing and massive photovoltaic (PV) connected to the distribution network(DN), there will be two-way power flow in traditional DN. As one indicator to measure the maximum amount of active power that certain bus of distribution network (DN) can be injected, the hosting capacity of DN is to be a research hotspot. This calculation method of hosting capacity of DN is presented based on optimal power flow (OPF)model and commercial solver. Based on the branch power flow equation with relaxation method, the maximum active power of renewable energy source (RES) that can be injected to DN is calculated precisely. An improved IEEE 33 buses case validates the correctness of the proposed calculation model.
... Nowadays, there is a growing market for smart grid technology. An embedded system and DSP processor are used to illustrate a transient fault protection technique in the article (Zhang, Hao, and Bo 2016). A coordinate phasor measurement unit (PMU) based adaptive distance protection technique was proposed in a research work (Lin, Guerrero, et.al. ...
... Extensive studies have analyzed the impact mechanism of various malicious attacks on power systems, including physical attacks (PAs) [4,5], cyber attacks (CAs) [6][7][8], and coordinated cyber-physical attacks (CCPAs) [9,10]. Since modern power systems have heavily adopted information technology to perform monitoring and real-time control tasks [11], the cyber-physical characteristics of secondary electrical components, especially protective relays [12], play a more important role in power system operation. Malicious attacks against protective relays are ...
... d ij = 1) are in the same states (c d i =c d j ). Constraint(12) indicates that disconnected edges (s d ij = 0) have no commodity flow (F d ij = 0). Constraint(13) guarantees commodity conservation at each vertex. ...
In recent years, power systems have been facing an increasing risk of malicious attacks. As modern power systems have a greater reliance on communication and automatic control systems, coordinated cyber-physical attacks will cause more serious consequences for the reliable power supply than traditional malicious attacks. To enhance the resilience of power systems against coordinated attacks, a defense method to allocating hardening resources is proposed in this paper considering the full substation topology and the multi-stage response process of power systems. The problem is formulated as a tri-level optimization model involving interactions among the defender, the attacker, and the operator, in which the synergy impact of three attack forms is considered, i.e., physical attacks causing short-circuiting, cyber attacks causing protective relay misoperation, and cyber attacks causing protective relay maloperation. A graph-based analytical model is established to characterize the impact process of such coordinated attacks on power systems. Case studies are conducted on the IEEE RTS 24-bus system. The influence mechanism of coordinated cyber-physical attacks involving protective relays on power systems is systematically revealed. Results show that the proposed method can effectively defend against the above-mentioned coordinated attacks, and enhance the resilience level of power systems. In addition, a sensitivity analysis is implemented on the influence of attack resources and defense resources on the unserved energy at each stage of the system.
... The relay protection device is important to ensure the safe and reliable operation of the power system [1][2] . This is because the aggressive deployments of smart grids [3] , electronic transformers, merging units, intelligent terminals, and other equipment are widely used in smart substations [4] . ...
Aiming at the network characteristics of a smart substation redundant network with complex communication messages, a large amount of interactive data, and high real-time performance, the test model of multiple submachines in a High-Availability Seamless Redundancy (HSR) loop network is analyzed. The requirements of packet types, size, and transmission speed are evaluated, and a hardware solution based on a multi-core Digital Signal Processor (DSP) and Parallel architecture FPGA is designed. The multi-core interaction strategy of DSP software and the multi-port high-speed communication method of FPGA are proposed, and the inter-core communication (IPC) interrupts and shared memory to achieve fast data migration between cores, based on the Serial RapidIO (SRIO) to complete high-speed message transmission. The throughput, delay, packet loss rate, and error frame detection functions are realized, tested, and verified, providing theoretical and practical support for the evaluation of redundant network performance of smart substations.
... Transient signal method is to record the signals of voltage and current at the moment of the fault occurring by a high-speed data acquisition device. Intelligent algorithms such as wavelet packet, Hilbert transform and differential filtering have been used to extract transient features components and select fault line by comparing transient feature signals (Xue et al., 2014;Lai et al., 2015;Zhang et al., 2016;Sun et al., 2017;Xu et al., 2018;Zhang et al., 2018). Although these two types of methods can effectively improve the accuracy of fault line selection, both require the installation of additional hardware in the distribution network, which is more economically expensive and difficult to implement, so they are not widely used. ...
It is important to select the fault line rapidly when single-phase grounding fault occurs in the small current grounding system. The fault information acquisition of existing methods generally need hardware modification, so the high cost makes it difficult to apply to the power grid in underdeveloped areas. Taking that into consideration, this paper proposed a method of steady-state information small current grounding fault line selection based on Optimization Spiking Neural P Systems (OSNPS). The method only needs the steady-state voltage and current data of the dispatch side to effectively identify the fault line, which greatly improves the range of application. According to the characteristics of power dispatching big data, the objective function is established and the normalized model parameters are optimized by OSNPS to improve the accuracy of fault line selection stably. Furthermore, PSCAD/EMTDC is used to simulate the small current grounding system, the main factors affecting the accuracy of fault line selection are analyzed and the relationship between fault information features and fault identification accuracy is revealed. What’s more, It is pointed out that the model parameters without optimization may have line selection failure. Finally, specific examples are given to verify that the model parameters optimized by OSNPS can effectively improve the accuracy of fault line selection.
... The peak value of TEV can reach tens of kV, and it has higher frequency components than VFTO. In the development of a smart grid, there are new requirements for power system protection and control Zhang et al., 2016). At present, intelligent equipment is widely used in the power system, especially in relay protection (Nan et al., 2018;Yang et al., 2021). ...
The disconnector switching operation in GIS not only generates very fast transient overvoltage (VFTO) in primary equipment, but also couples to the secondary system, which affects normal operation of the secondary equipment. In this study, aiming at the conducted disturbance caused by the disconnector switching operation of the 1,000-kV UHV GIS test circuit on the secondary cable, a broadband equivalent circuit model of the potential transformer and the grounding grid is proposed based on the vector fitting method and the impedance synthesis method, and the accuracy of the model is tested. On the basis of this model, the conducted disturbance voltage of the secondary cable core is obtained by combining the measured typical disturbance source waveform. The research results of the influencing factors of conducted disturbance show that the amplitude of the disturbance voltage generated by the capacitive conduction is higher than that generated by the resistive conduction, but the main frequency of the resistive conducted disturbance voltage is higher. The amplitude of the conducted disturbance voltage will decrease with the increase of the length of the cable and the length of the grounding wire. The single-ended grounding of the secondary cable shield at the GIS side will cause serious disturbance voltage. The research results of this study will be beneficial to the protection of secondary cable electromagnetic disturbance in the intelligent substation and have reference significance for the implementation of secondary equipment protection measures in the intelligent substation.
