Substation System Research Articles

Research of Communication Interface between PMS2.0 and IEC61850 based on Model Mapping

In recent years, the State Grid has been vigorously developing PMS2.0 system and intelligent substation system based on IEC61850 standard. Because the two systems follow different standards, the models are not uniform and the information is difficult to share. In this paper, the mapping relation between the two models is found by analyzing and comparing the structure of the IEC61850 model with that of the PMS2.0 model. Using the MMS communication protocol in IEC61850 Standard, the MMS communication module is designed on the CompactRIO platform of NI Company to realize the data interoperability between PMS2.0 and intelligent substation System. The simulation test effect is good, which shows that the design is effective.

Power system harmonic and interharmonic estimation using Vortex Search Algorithm

In this paper, a vortex search algorithm (VSA) based method designed to estimate power system harmonics and interharmonics for highly time-varying cases is presented. Time-variation in the power system is due to the nonlinear and stochastic loads such as electric arc furnaces (EAF) and it is one of the major cause of the power quality problems. The proposed algorithm is tested on both synthetic signals and also field data obtained from transmission system substations supplying EAF plants. The results are compared with other search algorithm-based methods reported in the literature and shown that VSA algorithm exhibits better estimation performance and has less computational complexity. In addition, the VSA algorithm is also tested on real field data and the results are compared with those obtained by Kalman Filtering method, which is claimed to provide fastest results in the literature. It has been shown that the proposed method has better convergence results in noisy environment with less computational complexity.

Formal reliability and failure analysis of ethernet based communication networks in a smart grid substation

AbstractSecure and continuous operation of a smart grid substation mainly depends upon the reliable functioning of its communication network. The communication system of a smart substation is typically based on a high performance Ethernet communication network that connects various intelligent embedded devices, such as Intelligent Electronic Devices (IED) andMerging Units (MU), to ensure continuous monitoring, automation and efficient demand response of the smart substation. Traditionally, Reliability Block Diagram (RBD) and Fault Tree (FT) methods are used to develop reliability and failure models for these communication networks by considering the failure characteristics of their substation intelligent embedded devices and other components, like transformers and circuit breakers. These resulting reliability and failure models are then analyzed using paper-and-pencil methods or computer simulations, but they cannot assure accuracy in the analysis due to their inherent limitations. As an accurate alternative, we propose a methodology, based on higher-order logic theorem proving, for conducting the formal RBD and FT-based reliability and failure analysis of smart substation communication networks, respectively. This paper also describes a sound transformation of smart grid FT models to their equivalent RBDs - a well-known method to reduce the complexity of FT-based failure analysis. Some ML-based tactics have been developed to automatically compute the reliability and failure probability of smart grid substations for practical purposes.

Vanadium redox flow battery parameters optimization in a transportation microgrid: A case study

This paper addresses the concept of vanadium redox flow batteries as stationary energy storage for achieving optimum parameters of energy and cost-effectiveness in transportation microgrids. Such energy storage has two main purposes: to utilize the energy recovered from braking trains, and shave power peaks. With abovementioned purposes, economic feasibility is the main driver of measures to optimize the battery parameters, including joint energy and power capacity, as well as and energy management strategy parameters. The optimization results obtained from the genetic algorithm and particle swarm optimization algorithm were compared, and the comparison demonstrates that the second method operates more sufficiently. The case study shows that the implementation of the proposed battery system in a traction substation allows one to achieve approximately 7 year payback period and decrease peak power and daily consumption by 581 kW and 1.77 MWh, respectively. In addition, sensitivity analysis was conducted to determine the impact of certain factors and battery parameters on the resulting payback period. The results show that the effect of deviation of energy management strategy parameters from optimum values on payback period is four times more profound than deviation of battery parameters, which demonstrates how important energy management strategy is.

Analysis of wind-induced response of down lead transmission line-connection fitting systems in ultrahigh-voltage substations

Based on a certain 1,000-kV ultrahigh-voltage substation, a finite element model is established for the down lead transmission line (DLTL)-connection fitting system using the ABAQUS software. The mechanical properties of the bushing terminal and the connection fitting under equivalent static loads corresponding to various wind speeds are analyzed. The analytical results are compared with experimental results to verify the correctness of the model. On this basis, the effects of the connection fitting type, the DLTL system type and the suspension location of the DLTL system on the mechanical properties of the bushing terminal are discussed. The dynamic response of the DLTL-connection fitting system to various wind speeds is investigated through simulation. The results are as follows. From a mechanical perspective, the bushing terminal with an “I”-shaped connection fitting is notably superior to that with a “U”-shaped connection fitting; however, the “I”-shaped connection fitting system must be strengthened. Compared to the “λ”-shaped DLTL system that is currently and commonly used, the “π”-shaped DLTL system is more reasonable, but the offset of its suspension point must be controlled (0–3 m is recommended). When considering the vibration caused by pulsating winds, the maximum stress on the bushing terminal increases significantly, and premature failure is risked. In engineering design, a dynamic amplification factor no less than 2.0 is recommended for use to consider this adverse effect.

Electrical peak load forecasting using long short term memory and support vector machine

Electrical load forecasting is usually a univariate time series forecasting problem. In this case, we use the machine learning approach based on Long Short Term Memory and Support Vector Machine. Accurate the peak electric load forecasting. The time series or data set of the peak electric load recorded from the Substation system in Lhoksumewe, Indonesia. The main aim of this paper to predict and evaluate the performance of peak electric load at the substation for six months. The results obtained in the study, the LSTM and SVM are proving useful for peak electrical load forecasting. The resulting point both of machine learning technique based on LSTM and SVM are a possibility for analysis data for such purposes.

Switching impulses of overvoltage phenomena of power system in 220 KV transmission lines inter between substation case analysis

This paper illustrates of switching impulse over voltage due to changing of the load condition to the existing 220 KV transmission lines as well as substation system. The study of performed by computer based method using ATP simulations. The details of the system modeling represented for various equipments designs and selection of the power system. These phenomenons are effects on the shunt reactor and loads on or off over condition will investigate. This analysis of the overvoltage occurrences under the transients small optimal determining from the overvoltage withstand in the equipments and continuous supply as well as less disturbance of the power system[1].

New auxiliary services system in a transmission substation in the presence of a renewable energy source PV

The exploitation of transmission or distribution network of substations requires auxiliary electrical sources with low continuous and alternative voltage. Actually, DC and AC power supplies of auxiliary services are insured by batteries, generator, rectifiers and inverters. In this work, we want to add another source based on renewable energies to obtain a hybrid system and reinforce the main service of transformer substations. The addition of this source will influence operating mode of the existing systems, upgrade the quality of supply and reduce the losses of the transport network. The work presented in this article is a contribution to a good modeling of such system and especially different components of a photovoltaic power station connected to the grid of transmission substations. The main components of a connected PV plant are modeled and simulated in Matlab / Simulink and ETAP.

Improving the efficiency and reliability of RPA systems of digital step-down substations and digital grids

The article discusses examples of synchrophasor measurement (SPM) technology application for implementation of inherently selective protection for 35-220 kV step-down substations and 6-20 kV distribution points.

Study of Internet of Things Technology Applied in Intelligent Substation Auxiliary System

In order to improve the linkage of related auxiliary systems in intelligent substation and realize the complete monitoring and control functions of the equipment in the station, this paper integrates the technologies of Internet of Things, edge computing and big data to establish an auxiliary system of IoT intelligent substation. The overall structure of the system is introduced in detail. The effective calculation and reduction of the computing task of a single edge node is achieved by the application function and the edge calculation algorithm of task balancing allocation and scheduling, effectively improving the immediacy and security of the intelligent substation auxiliary system of the Internet of Things. The construction of transportation inspection has certain guiding significance.

Research on the Harmonics Penetration Characteristics of the Traction Network to Three-Phase 380 V Power System of the Traction Substation and Suppression Scheme

To reveal the penetration characteristics of high-frequency harmonics of the traction network to the three-phase 380 V power system in the traction substation (TSS), the harmonic equivalent circuit model and harmonic penetration mathematical model of the two-phase to three-phase Scott-T transformer are established. Through the power quality measurement and harmonic analysis, the results indicate that the high-frequency harmonics in the traction network will severely penetrate the three-phase 380 V power system, which will cause almost the same degree of harmonic distortion, verifying the correctness of the harmonic penetration model. To filter high-frequency harmonics in TSS, a novel structure of high-pass filter (HPF) is proposed that features with high-pass characteristic at high frequencies while high-impedance at fundamental frequency. Furthermore, a set of three-phase experimental device is developed, and a long-term filtering experiment in the TSS is performed. The experimental results show that the novel HPF experimental device can effectively filter out high-frequency harmonics of the three-phase 380 V power system, and have almost no loss and reactive power. The feasibility and effectiveness of the suppression scheme based on the novel HPF are verified.

Research on Interface Mode and General Information Transmission Technology in smart Substation

Through the analysis of the system architecture of smart substation, the interface mode and information transmission protocol between secondary equipment and primary equipment are defined. The general information transmission protocol for data acquisition and control instruction transmission is studied, which improves the reliability and security of the secondary system of smart substation.

Design of Online Calibration Device for Electric Energy Metering Based on GPS Synchronous Sampling

The error checking of electric energy meter is the basic function of on-line monitoring system of electric energy metering device. A kind of on-line error checking device for electric energy metering system of digital substation is studied. It includes signal sampling module, remote pulse acquisition module, GPS synchronization module and wireless communication module. The hardware design scheme and software design idea of the main link are introduced in detail. DDS power frequency conversion circuit is designed with AD9850 chip. The designed system has the function of high and low range adjustment of input voltage and current, and the error accuracy is better than 0.05, which can greatly improve the calibration efficiency.

Analysis and design of an intelligent fire alarm system for UHV Substation

At present, the fire accidents caused by power equipment operation in substations are on the rise, especially for large transformers and high-resistance oil-filled equipment. The fire hazard and harm of electric power equipment can not be ignored. With the improvement of substation automation, Higher Requirements are put forward for fire safety, reliability, fire efficiency and preventive measures, so it is necessary to analyze and design the intelligent fire control system of UHV substation.

Concept of control and data acquisition system for modern digital power substation

The article deals with the issue of standardization of approach to definition of modern digital substation is considered. The approaches proposed and partially implemented by equipment manufacturers are described, such as data collection and processing by means of relay protection and automation with the use of proprietary algorithms, wireless and optical current and voltage sensors, etc. The authors propose the use of a unified system for collecting and processing data generated and used in the operation of an electric substation. The structure of the signal transmission system for the main groups of electrical power equipment is described, the requirements for the predictive diagnostics system that allows maintaining the equipment based on its technical condition are described.

Diagnosis and Research on Local Overheat Fault of Main Transformer

The main transformer is a transformer used to deliver power to a power system or user in power plants and substations. This paper introduces the use of infrared imaging detection technology and gas chromatography analysis technology as the main means to accurately diagnose a local transformer overheating fault. The article elaborates the diagnosis method, diagnosis process and treatment suggestions, and deeply analyse the causes of the local transformer overheat fault, and provides reference for the diagnosis and analysis of the same type of transformer fault.

Lead-Acid Battery Sizing for a DC Auxiliary System in a Substation by the Optimization Method

Lead-acid batteries are the most frequently used energy storage facilities for the provision of a backup supply of DC auxiliary systems in substations and power plants due to their long service life and high reliability. It is possible to define the load in these systems, therefore the IEEE 485 Standard can be used for the selection of batteries according to the conventional method of selection. Special attention is paid in the paper to the technical selection of a lead-acid battery, which depends on its operational reliability that decreases with battery aging. It is defined by the extent of maintenance during its service life. A cost analysis was also carried out, which took into consideration maintenance and procurement costs, as well as the costs of the related air conditioning that keeps the prescribed temperature and ventilates the battery room. The impact is shown of selecting a lead-acid battery on the battery room’s operating safety when charging. The final selection of lead-acid battery is performed using an optimization algorithm of differential evolution. Using the optimization process, the new battery selection method includes the technical sizing criteria of the lead-acid battery, reliability of operation with maintenance, operational safety, and cost analysis. Two cases of selection of lead-acid batteries for the backup supply of a DC auxiliary system in a transmission substation are presented in the paper, where the input data were determined based on measurements in an existing substation. A comparison is made between the existing conventional and new lead-acid battery selection method based on optimization.

Spectral approach to the estimation of the time series of the power change in the substation metering units and its application in the control modes of substation electricity metering systems

The wide possibilities of modern interval metering devices installed at substations of distribution grid companies are not fully used today. In the process of measuring the electrical parameters of the network meters, there may be abnormal modes of electricity metering substations, resulting from intentional or negligent actions of staff, failure of existing equipment or parts thereof. The considered circumstances lead to large economic losses of electric power enterprises, expressed in the underestimation of electricity. One of the effective ways to solve this problem is the use of intelligent techniques to identify incorrectly operating metering stations of the substation network, as well as the development of an optimal model of an automated multifunctional information and measuring system for industrial use and software implementation. The purpose of the study – the development of methods of control and diagnosis of normal operation of the substation electricity metering system, determined by compliance with the reliability of electricity metering substation information and measurement systems. On the basis of the offered method the algorithm of control and diagnostics of modes of operation of the information-measuring equipment of system of the account of the electric power of substations is offered. The software for a two-level multifunctional measurement system combining the functionality of an automated electricity metering system, a system for monitoring and diagnosing the modes of operation of the information and measuring complex of substations, and a system for monitoring the quality of electricity has been developed. The results of the research were used in the development of recommendations for the construction of automated information and measurement systems based on existing power metering systems of substations for distribution grid companies. The developed technique and the corresponding algorithm of control and diagnostics of abnormal operating modes of information-measuring complex of substations allow to quickly determine the technical condition of the metering system of substations, to plan corrective measures to eliminate violations.

Design of an Industrial IoT-Based Monitoring System for Power Substations

The Internet of Things (IoT) concept allows objects to share data through wired or wireless connections for communication purposes. The industrial Internet of Things (IIoT) is an extended concept of IoT that refers to an integration of data acquisition, communication, and processing on a real-time network. Currently, IIoT has been involved with the development of smart grids in many applications. As the operation of power systems is extremely time-critical, low-latency communication needs to be considered for most control and monitoring applications. Real-time capability of IoT is considered as a key feature for monitoring and control applications of power systems. Therefore, system operators can use the real-time monitoring system to provide better decisions for both technical- and financial-related matters. In this article, a high-speed IIoT-based monitoring system with recording functions is developed and implemented for a power system substation. Due to the high reliability and processing speed of field-programmable gate arrays (FPGAs), an FPGA-embedded controller is adopted in this system. The IoT platform also provides remote visualization for system operators in real-time. This article mainly aims to provide a practical application that was implemented and tested in a real-power substation. The system incorporates the features of an IoT platform with the needs of high-speed real-time applications while using a single high-resolution time source as the reference for both steady-state and transient conditions.

A −12.3 dBm UHF Passive RFID Sense Tag for Grid Thermal Monitoring

This paper presents an ultra-high-frequency (UHF) passive sense tag for electrical grid and substation thermal monitoring, with emphasis on the tag system optimization and the design of a low power embedded temperature sensor. The designed tag achieves a sensitivity of $-$ 12.3 dBm under active temperature monitoring operation, which is the state of the art among existing UHF passive temperature sense tag products. The sensing inaccuracy of the tag is $\pm$ 2.5 $^{\circ }$ C (3 $\sigma$ ) from $-$ 25 to 120 $^{\circ }$ C after a low-cost wireless single-point trim. An antimetal ceramic-packaged tag was tested by attaching to a ring main unit in the substation and complete tag system demonstrated robust wireless operation with a sensing distance of 3.5 m. The combination of batteryless and wireless operation, high sensitivity, wide sensing range, and small incident-power-dependent error ( $\pm$ 0.2 $^{\circ }$ C) makes this tag suitable for the target applications.