Substation Operation Research Articles

Dangerous Points and Safety Control in Substation Operation and Maintenance

Dangerous Points and Safety Control in Substation Operation and Maintenance

Filtering for the Interference Signal Caused by Grounding Potential Difference in High-Voltage Disconnector

The disconnector operation in the high-voltage substations forms a very fast transient overvoltage (VFTO), which leads to a sudden rise in local grounding potential. Due to double grounding of the secondary cable, the current transformer signal is interfered by the grounding grid potential difference. To study the mechanism of the interference signal, a simulation model based on the electro-magnetic transient program is built and the coupling path of the grounding grid potential difference is analyzed. According to the characteristics of interference signal, an adaptive algorithm is put forward and it mainly consists of three parts, including starting element, decision algorithm, and filtering algorithm. By selecting the appropriate parameters of wavelet transform, the filtering algorithm can discompose and reconstruct signal to remove the interference signal. The simulation results demonstrate that the filtering algorithm can effectively eliminate the interference signal caused by the grounding grid potential difference, with a 91% reduction of the root mean square error and a 135% improvement of the signal-to-noise ratio. Moreover, the accuracy of the measured data is ensured and the reliability of the relay protection is improved.

Research and Application of a New Type of Substation Transportation Inspection Simulation Training System

For the shortcomings of the existing professional training for substation operation inspection, this paper proposes a design of a new type of substation operation inspection simulation training system based on networking, adaptive learning, gamification and other technologies. The system solves the problem that substation operators lack modern training tools and cannot carry out networked simulation learning, and conduct targeted and personalized learning based on user knowledge and skills. The system lacks guidance and evaluation functions in the learning process, and the system lacks interest and cannot effectively stimulate learners’ interest in learning and other issues. The research results of this article have been successfully applied in the Gansu Electric Power Company and have obtained good training effects.

Analysis of the Operating Modes of the Stationary Energy Storage Device in DC Railway Power Supply System

Abstract This article analyzes the operating modes of the energy storage. The aim was to conduct laboratory tests in conditions similar to real energy storage and to analyze its basic electrical parameters. A special measuring system has been created for laboratory testing. Real tests took place in the traction substation in Mińsk Mazowiecki, where the energy storage was included in the traction substation system. Based on the laboratory tests carried out and in real conditions it was found that the use of energy storage in the electric traction supply system is justified. It is adapted to work as a device supporting the operation of the traction substation and the section cabin.

The Design of Single-chip Microcomputer for the Project of "Increase 485 Bus Communication Speed”

The operation and maintenance of traditional substations is not timely due to the huge cost of manpower and material resources. In the context of "ubiquitous power Internet of Things", the operation and maintenance of substations uses a large number of sensor equipment. However, the traditional rs485 bus is difficult to transmit large-capacity data such as waveform curves and images in real time, and the optical fiber transmission form of industrial Ethernet will bring higher costs, which will hinder real-time monitoring. This project intends to achieve impedance matching by adjusting the resistance of the pull-up and pull-down resistors and terminal resistors, thereby increasing the communication rate of the rs485 bus. To this end, we specially designed a simple STM32 single-chip microcomputer to match the realization of the project. The hardware part of this design adopts the STM32F103RCT6 single-chip microcomputer as the main control chip, using MAX3485 as the serial port chip, and at the same time choosing the resistance and capacitance of 0805 package, using AMS1117 Packaged voltage regulator chip.

Design of automatic robot with electrolytic wiring for isolating circuit breaker

Isolation circuit breakers are used in power stations to isolate voltages, and isolate the equipment to be repaired from live parts to form a safe operating space. In order to meet the needs of on-site maintenance and test of the new generation intelligent substation, avoid the need to stop other electrical equipment during the maintenance of the isolation circuit breaker, reduce the scope of equipment power failure and shorten the system debugging period, this paper proposes a design method of automatic live line disconnection robot for isolation circuit breaker, which can meet the requirements of bus clamp removal and installation, and improve the isolation of new generation intelligent substation Operation and inspection level of circuit breaker. The specific method is to design a mobile robot lifting platform, through the cooperation of manipulator, controller, arc strike rod, camera and other tools to realize the live line disconnection operation of three-phase bus. In this paper, 3D modeling and simulation show that the robot design scheme is feasible.

IoT based kWh Meter Recorder System for Electrical Substation

The plan to abolish the substation operator raises new problems in reading the electrical energy stand, which at present all State Electricity Company units conduct it manually. This paper aims to provide a cost-effective meter data recording system to replace manual reading. The proposed solution is developed using WI-FI based internet of things (IoT) technology. Our proposed solution is implemented as a meter-recording device installed at the substation. Since deployed in December 2018, this tool works very well. Since it actively supports East Java’s performance in the pilot distribution control unit, it can be implemented in other units.

Vulnerabilities and countermeasures in electrical substations

The impending and continued threat of cyberattacks on modern utility grids has called for action from the different stakeholders of the electricity sector. This calls for a thorough investigation and review of the weaknesses present in the distribution substations – the backbone of the grid – that can attract attackers to achieve their malicious objectives. The present survey deals with this issue and identifies both the common and specific vulnerabilities present in substations that can be exploited by potential attackers. This work approaches the topic, for the first time, from an attacker's perspective, in order to categorize the possible attack vectors that could be used to first access the substation network, and then disrupt the substation operations under the purview of IEC standards. The reported literature in the field was critically analyzed from an attacker's perspective to highlight the potential threats that can become a liability in cyberattacks on substations. Countermeasures pertaining to these cyberattacks are then detailed and the main elements required for a comprehensive electrical substation cybersecurity solution are finally outlined.

Substation operation ticket system based on natural language analysis and intelligent reasoning

[Background/Reason] The operation ticket system is an important measure to ensure the safety of substation operation. At present, the issuance and review of substation operation tickets rely on manual operation knowledge and experience, and there are problems such as low work efficiency, lack of standardization, and human error. The risk of grid operation is reduced. [Method/Process] This paper proposes a substation operation ticket system based on natural language analysis and intelligent reasoning. It uses typical/standard operation tickets as the basic corpus and builds a natural language analysis model based on manual labeling to achieve compliance with the operation tickets. Sexual inspection, deduction and comparison of equipment status. Finally, combining the primary wiring diagram of the substation and the operation ticket to construct the equipment relationship knowledge map and the equipment operation knowledge map, use the Neo4j graph database for storage, and realize the intelligent drafting of operation tickets based on the graph search method. [Results/Conclusions] The research results have been implemented and applied in three substations in a certain area, verifying that the system has a high degree of intelligence and versatility, and can effectively solve the existing problems of standard invoicing and audit errors, and improve operation The work efficiency of personnel and the safety control level of power grid substation operation.

Ensuring timely repair of power transformers based on data of complex diagnostics

Timely diagnosis of power transformers is an essential component of ensuring reliable and safe operation of power stations and substations, on which the reliability of the power system depends. Detection of defects in the initial stage allows to maintain reliable operation of transformers, helps to define the "life cycle" and simplify the planning of their replacement. The paper presents an analysis of existing approaches to the creation of power equipment diagnostics systems using the example of power transformers. A neural network model has been developed, demonstrating the possibility of using power transformers to estimate the current residual resource based on the analysis of available diagnostic data.

Research and Application of Visual Monitoring Technology of Protective Equipment Based on Virtual Model

Aiming at the problem of heavy workload and tight time for daily operation and maintenance of smart substations, a visual monitoring technology for smart substation protection equipment based on virtual models is proposed, and a visual monitoring system for protection equipment is established. The article establishes the virtual model of the protection equipment panel, configures the association relationship between the graphic elements in the virtual model and the data set entries of the protection device and the optical fiber link, and establishes the logical operation model of the graphic elements.The visual monitoring system for protection equipment collects the data set entries of the protection equipment and the status values of the optical fiber link data set entries, simultaneously display the status of the primitives in the virtual model of the protection device panel according to the status value of the data set entry of the protection device. The visual monitoring system of intelligent substation protection equipment is applied on-site to verify the effectiveness of the technology.

Research on Key Technology of Primary Protection System in Intelligent Substation

The smart substation in this paper is a model. Through the research of its primary system, the project construction scale and design scope, electrical main wiring, short-circuit current and main equipment selection, insulation coordination and overvoltage protection, cable facilities, power distribution equipment, etc. To conduct research. Analyze application status detection, fully optimize design, and improve operation and maintenance management. Combining the online monitoring and sequential control operation of the intelligent substation, the research of the secondary protection design scheme is carried out. It analyses the system dispatch automation, integrated power supply system, system and station communication, secondary equipment cabinet and layout, component protection and automatic equipment, etc., focusing on online monitoring, sequential control operation and operation and maintenance management. With the maturity of online monitoring technology, the realization of sequence control operation technology and the application of optical fibre network in real-time systems, the safety level and operation and maintenance management of smart substations will surely be better improved.

Research on 110kV oil impregnated paper capac-itance graded transformer bushings based on the design principle of equal capacitance and steps

The oil impregnated paper capacitance graded transformer bushings serves as the external connection device of the transformer to support and connect the insulation, and its insulation state is related to the safe and stable operation of substation equipment.In this paper, a simulation model of 110kV oil impregnated paper capacitance graded transformer bushings is constructed on the commercial finite element software platform based on the actual size of the bushing and the principle of equal capacitance and steps. The paper calculate the potential and radial electric field distribution of the bushing under the normal working voltage, and analyze the influence of the aluminum plate on the radial electric field distribution of the bushing, verifying the rationality of the design principle based on equal capacitance and steps.

Detection and Location of Safety Protective Wear in Power Substation Operation Using Wear-Enhanced YOLOv3 Algorithm

Wearing personal safety protective equipment (PSPE) plays a key role in reducing electrical injuries to electrical workers. However, substation employees often ignore this regulation due to lack of safety awareness and discomfortable feeling of wearing PSPE. Therefore, it is necessary to develop a detection algorithm for PSPE and workers to build real-time video surveillance systems in power substations. In this paper, a wear-enhanced YOLOv3 method for real-time detection of PSPE and substation workers is proposed. The gamma correction is first applied as the preprocessing method to highlight the details of the operators and data augmentation is performed. Next, K-means++ algorithm replaces K-means in wear-enhanced YOLOv3 method to derive the most suitable prior bounding box size and lift the detection speed. Then, the proposed method can be quickly and effectively trained based on transfer learning. Finally, extensive experiments are carried out on a dataset of images about usage of safety helmets, insulating gloves and boots. Using the proposed method, the mean average precision is improved by over 2% and the frames per second is the highest compared with other typical object detection methods, which illustrates the effectiveness of the wear-enhanced YOLOv3 method for PSPE and workers detection.

A Sequential Decision-Making Process for Optimal Technoeconomic Operation of a Grid-Connected Electrical Traction Substation Integrated With Solar PV and BESS

Ensuring the provision of the increasing power consumption and maintaining the power quality (PQ) are considered to be the major challenges for electrical traction substations (TSSs) due to their dynamic characteristics, which render their power demand and electrical behavior to be highly complex. Solar photovoltaics (PVs) and battery energy storage systems (BESS) can be reliable options for integration with the TSSs, the prerequisite, however, is to devise the appropriate approaches for the demand management (DM) and maintaining the PQ of such a system. In this article, a strategy is proposed for the optimal technoeconomic operation of the TSSs using a sequential decision-making process (SDMP). In the first layer, the DM is formulated so that it can address the requirements of the integrated system and the uncertainties. The second layer optimizes the limited capacity of the PV/BESS converters for the mitigation of the unbalances and the reactive power compensation. Moreover, a comprehensive modeling framework incorporating the SDMP is presented that lends itself to use as a robust platform for the realistic modeling of the TSSs, BESSs, and PV systems. The framework is utilized to demonstrate the effectiveness of the proposed SDMP for both the DM and improving the PQ of the TSS, which are validated using different case studies.

디지털변전소 상호운용성 검증시스템 개발

Since KEPCO’s digital substation is not composed of a single manufacturer’s device, but consists of 4 to 6 different manufacturers’ devices, interoperability between devices is considered very important. IEC 61850 International Standard does not define a single way of expressing all information that intelligent electronic devices in substations must implement, but allows the freedom to implement it differently for each manufacturer. The reality is that the operating environment for S/W implementation, communication library, operation method for system operation, and response method for communication failures differ from manufacturer to manufacturer. For this reason, compatibility problems between devices occurred from the beginning of the introduction of digital substations and caused obstacles in substation operation. In this paper, by analysing various compatibility problems that occurred at the site, it explains digital substation interoperability test-bed that can select interoperability issues rather than simply device failures and execute test procedures to verify them in advance, and the verification system that can automatically carry out the whole test process.

A Deep Learning-Based Cyberattack Detection System for Transmission Protective Relays

The digitalization of power systems over the past decade has made the cybersecurity of substations a top priority for regulatory agencies and utilities. Proprietary communication protocols are being increasingly replaced by standardized and interoperable protocols providing utility operators with remote access and control capabilities at the expense of growing cyberattack risks. In particular, the potential of supply chain cyberattacks is on the rise in industrial control systems. In this environment, there is a pressing need for the development of cyberattack detection systems for substations and in particular protective relays, a critical component of substation operation. This article presents a deep learning-based cyberattack detection system for transmission line protective relays. The proposed cyberattack detection system is first trained with current and voltage measurements representing various types of faults on the transmission lines. The cyberattack detection system is then employed to detect current and voltage measurements that are maliciously injected by an attacker to trigger the transmission line protective relays. The proposed cyberattack detection system is evaluated under a variety of cyberattack scenarios. The results demonstrate that a universal architecture can be designed for the deep learning-based cyberattack detection systems in substations.

Problems of the use of renewable energy sources in the structure of railway power supply

The paper presents the main indicators of the renewable energy sources in the railway transport structure of European countries. A new structure of railway power supply systems, energy storage systems and control algorithms under the conditions of stochastic mode of renewable energy sources operation are defined as the main problematic issues. Further directions for sustainable development of such systems and factors that influence the modes of operation of traction substations and electric networks were identified. Average power and a random component are two criteria that were used to build local systems. The paper presents the real schedules of daily load on the traction substation terminals and solar insolation with determined power distribution changes. The power deviations indicators depending on the time interval and the type of generation were determined. A normal law of distribution of a random component was determined as a result of all calculations. It is possible to determine the shortage or excess of electric power in the local system in a certain area and to plan the direction of its development in the near future by analyzing the nature of the determined average power change.

Fault Identification and Remote Operation of Receiving Substation and Auxiliary Substation using IoT

Fault Identification and Remote Operation of Receiving Substation and Auxiliary Substation using IoT

Distributed generation placement in distributive substations analysis using Markov Chain Monte Carlo model considering the reliability of power supply

Proper operation of the power substations is of great importance for power network reliability, stability and uninterrupted power supply. Distributed generation provides higher reliability in power supply, but still, there are contingencies in the electric power production and supply process, which lead to outages in the power supply. In this paper, a method for substations’ reliability estimation with distributed generation is presented based on Markov Chain Monte Carlo method. The method considers the possible substation operation states and using random number generator in MATLAB, it simulates faults and calculates the substations’ reliability. The method is demonstrated on two cases of 110/35 kV substations, each consisting of two transformers and distributed generator, analysing the best placement for the distributed generation.