An Integrated Distribution Grid Protection System Using 5G URLLC

It is well known that EMI arises from any operation that interrupts or changes an electrical current. During switching operations in substations, very fast, high field transients occur which can adversely affect, whether by radiated or conducted interference, the electronic equipment in equipment rooms unless it is adequately protected. The environment in which this equipment is installed therefore needs to be fully characterised in terms of electromagnetic interference levels. With this knowledge it is possible to provide adequate immunity for electronic equipment, and design efficient, effective and reliable protection, control and monitoring systems. The paper identifies two areas where the IEC 61000-4-10 Standard appears to be deficient. These are the required test frequencies of 10 kHz and 10 MHz, and testing at these frequencies are recommended at a repetition rate as determined by the formula given in the Standard.

The development of the fast protection system (FPS) was driven by the critical need to safeguard internal components of the accelerator from beam damage and minimize operational downtime. During accelerator operation, various faults can occur, posing a significant risk. The FPS acts as a rapid response system, initiating a shutdown signal to a reliable chopper system to prevent beam damage and ensure the operational availability of the accelerator. To meet the stringent shut off time requirements specific to critical faults, the FPS was designed to respond within 50 µs, while the total FPS time, including acquisition, redundancy, and processing, needed to be less than 20 µs. In order to achieve these goals, a customized FPS was developed for the RAON heavy-ion accelerator, utilizing the Xilinx ZYNQ system-on-chip (SoC). The FPS system comprised seven acquisition modules, one mitigation module with an embedded SoC, and employed optical fiber connections for efficient data transmission. This article provides a comprehensive account of the design, development, and testing of the FPS system. Experimental tests were conducted to validate its performance. These tests included verifying the accuracy of cyclic redundancy checks, acquiring interlock signals in short pulses, and measuring the delay time during abnormal signal occurrences. Of particular significance is the measurement of the total signal processing time for a 1 km optical cable in the RAON system, which was determined to be 9.8 µs. This result successfully met the stringent requirement of 20 µs for the FPS time. The ability of the FPS to operate within the desired time frame demonstrates its effectiveness in protecting the accelerator’s components from beam damage and minimizing downtime. Consequently, the FPS ensures the operational availability of the accelerator while maintaining the safety and integrity of its internal systems. By providing a detailed account of the FPS’s design, development, and testing, this article contributes valuable insights into the capabilities of the FPS in real-world accelerator scenarios. The successful implementation of the RAON-optimized FPS with the Xilinx ZYNQ SoC reaffirms its effectiveness as a fast and reliable protection system, thus enhancing the overall operational performance of the accelerator.

The complexity of an active distribution system with distributed generation (DG) is increasing day-by-day. Therefore, a reliable protection system is very necessary to satisfy customer demand. Apart from main grid supply, active sources are also available near load centers due to which traditional protection schemes fails to function properly. The magnitude of fault current during grid connected mode of microgrid, is much higher than islanded operation. Therefore, in most of the previous works, overcurrent protection crashes if its pickup current value is not changed when microgrid is shifted to islanded mode. In this paper, the current, voltage and frequency data sampled through PMU is processed to protect the system in both the operating modes. A centralized protection scheme is employed that takes frequency data and voltage phasor to differentiate between islanding and fault condition. Further, it detects the faulted feeder and sends trip command to respective relays within a tolerant time. This method is devised to work as backup protection when main utility grid is available. However, it can work as a primary protection during islanded mode, when local overcurrent relay fails to operate due to settings based on grid connected mode. A standard IEEE 15 bus system modeled in EMTP-RV is taken as test system for every analysis.

During faults in multi-terminal high-voltage DC systems, the disturbance will quickly become evident throughout the entire system. If DC breakers are included in such systems, the entire fault clearing process needs to occur within a few milliseconds. Therefore, DC line protection schemes based on telecommunication have previously been discarded by some authors as their performance is constrained by the communication delay. However, telecommunication-based detection methods offer some very favourable features, one being that selectivity can be achieved without coordination of settings. In this study, several telecommunication-based protection schemes are evaluated with regards to their minimum possible detection time when considering telecommunication delay. It is shown that they perform best during faults located at the remote end of a line, i.e. fault locations that are difficult to reliably detect using single-ended methods. Therefore, it is reasonable that the most reliable protection system will consist of both single-ended and communication-based methods because they complement each other well. Furthermore, it is shown that the travelling wave differential protection offers the shortest theoretical detection time due to the wave propagation delay being included in the formulation.

Design and implementation of a novel integrated timing and fast protection system for in-hospital AB-BNCT

One type of protective relay that requires coordination in an electric power system is the overcurrent relay (OCR) and ground fault relay (GFR). The OCR/GFR function is crucial for protecting equipment in a substation from short circuits between phases or phase-to-ground faults. Therefore, setting the OCR/GFR relay requires careful and precise calculations to ensure a sensitive, selective, fast, and reliable power protection system. Observations of faults at several substations in the Cilegon Technical Implementation Unit (UPT) revealed discrepancies in the OCR/GFR coordination. The method used was to calculate the OCR/GFR setting values on the feeder side and the main transformer side to analyze the protection system coordination.

The advanced digital reactor protection system (ADRPS) with diverse dual processors has been developed to prevent common-mode failure (CMF). The principle of diversity is applied to both hardware design and software design. For hardware diversity, two different types of CPUs are used for the bistable processor and local coincidence logic (LCL) processor. The Versa Module Eurocard-based single board computers are used for the CPU hardware platforms. The QNX operating system and the VxWorks operating system were selected for software diversity. Functional diversity is also applied to the input and output modules, and to the algorithm in the bistable processors and LCL processors. The characteristics of the newly developed digital protection system are described together with the preventive capability against CMF. Also, system reliability analysis is discussed. The evaluation results show that the ADRPS has a good preventive capability against the CMF and is a highly reliable reactor protection system.

Accurate classification between magnetizing inrush currents and internal faults is essential for reliable transformer protection and stable power system operation. Because their transient waveforms are so similar, conventional differential protection and harmonic restraint techniques often fail under dynamic conditions. This study presents a two-stage classification model that combines a self-organizing map (SOM) and a convolutional neural network (CNN) to enhance robustness and accuracy in distinguishing between inrush currents and internal faults in power transformers. In the first stage, an unsupervised SOM identifies topologically structured event clusters without the need for labeled data or predefined thresholds. Seven features are extracted from differential current signals to form fixed-length input vectors. These vectors are projected onto a two-dimensional SOM grid to capture inrush and fault distributions. In the second stage, the SOM’s activation maps are converted to grayscale images and classified by a CNN, thereby merging the interpretability of clustering with the performance of deep learning. Simulation data from a 154 kV MATLAB/Simulink transformer model includes inrush, internal fault, and overlapping events. Results show that after one cycle following fault inception, the proposed method improves accuracy (AC), precision (PR), recall (RC), and F1-score (F1s) by up to 3% compared with a conventional CNN model, demonstrating its suitability for real-time transformer protection.

Development and hardware implementation of a reliable protective relay data acquisition system

The utilization of phasor measurement units (PMUs) with protective relays is rapidly increasing in the existing power transmission networks for reliable monitoring, control and protection of complex power system. Thus, it is feasible to develop an effective primary and backup protection scheme for transmission lines by utilizing the information from PMU-cum-Relays. Regarding the conventional relays, it is observed that its operation is severely affected with the presence of events like power swings, load encroachment etc. In this paper, authors propose to utilize wide area monitoring system for backup protection of transmission lines using proposed phasor data concentrator (PDC) index, which is calculated at PDC using the measured frequencies from different PMUs. As the backup protection scheme is centrally executed at PDC, the proposed scheme do not require the coordination time, but do involve communication delays associated with the network. The effectiveness of proposed special protection scheme has been tested and validated on reduced NEREB 29-bus Indian power system with distributed generation sources using SINCAL and MATLAB softwares. The simulation results reveal that the proposed special protection scheme can enhance the protection strategy of transmission lines in smart electric grid.

Since the large fault inrush current threatens the safety of power electronic devices, the synchronverter should have the fault ride-through (FRT) capability and should be equipped with a reliable protection system. Therefore, it is important to study the transient fault characteristics of the synchronverter and propose its fault current estimation method. In this paper, by establishing the equivalent model of synchronverter, an asymmetric fault current analysis method using the instantaneous symmetric component method is proposed. In addition, the current components, peak value, peak time, time required for reaching two times of the rated current, and main influencing factors of the asymmetric fault current are also analyzed. It is found that the influencing factors mainly include the control loops of synchronverter, asymmetric fault type, line impedances, and fault occurring moment. Moreover, the time required to reach two times of the rated current is approximately within the range of one hundredth of a microsecond to five milliseconds. These fault current characteristics impose strict requirements on the response speed of FRT control strategies. Finally, the simulation and experiment results verified the correctness of the proposed analysis method.

This paper presents how the directional Overcurrent protection function can operate incorrectly on a Windfarm when providing reactive power support to the Transmission network. A reliable protection system is necessary for a functioning Windfarm. This paper identifies areas of vulnerabilities in the typical Relay Characteristic Angle (RCA) setting and presents a case study that demonstrates conditions where the selectivity of the Windfarm protection is compromised. A case is presented where the Overcurrent protection function can operate under normal operating conditions. A solution is presented that shows an RCA setting that would ensure the Windfarm can remain in operation when providing reactive power support.

The explosive rise of malware poses risks to Android developers and organization regarding security lapses and monetary losses. The dynamic nature, changing complexity and behavior over time, and increasing velocity and volume make it challenging for the malware protection community to provide a robust and reliable protection system. Due to these characteristics, conventional Android malware detection techniques, such as signature-based and battery-monitoring, cannot detect futuristic malware. Current research exploiting deep learning methods shows excellent performance compared to conventional and machine learning methods. However, the majority of the techniques are proposed for only binary classification. These classification models are tested on customized datasets. They do not provide the model’s effectiveness in terms of generalization, as the model’s accuracy might be good for some malware classes. Hence, providing a practical, robust, stable, and reliable malware model is still an open issue. Therefore, in this work, we propose an Attention-based deep learning model to detect categorical malware classes. The attention-based deep learning mechanism learns the malicious behavior of target classes. The attention mechanism filters and extracts the relevant information more effectively by focusing on the specific keywords in a target sample.

All devices in substation environments are susceptible to interference from various sources, such as adjacent power conductors, substation heating supplies running in close proximity to DC wiring, to presence of battery earth fault. Selection of appropriate tripping / intertripping devices is of paramount importance to avoid undesirable protection mal-operations. This paper discusses when and where tripping devices, such as opto inputs and tripping relays, should be used to ensure secure and reliable protection systems.

Installation of distributed generation in distribution grids may cause malfunctioning of conventional protection systems due to bidirectional flows and increased range of short-circuit current levels. Despite considerable efforts to address these challenges, development of low-cost, high-speed and reliable protection systems for active grids remains an open research question. This paper presents a new wavefront-based protection system for medium voltage lines of a substation in an active grid. The protection does not require voltage measurements and relies only on local current measurements and binary signals received from neighboring protection terminals. The fault occurrence is detected by capturing fault-generated current waves using Wavelet Transform. A faulted line in the protection zone is identified through comparative analysis of slopes' signs of current wavefronts obtained locally and from neighboring terminals. The proposed algorithm potentially offers high-speed and reliable protection of any number of interconnected lines, which is demonstrated on the IEEE 34-bus distribution system.