Three-phase Electricity Research Articles

Detection Method for Three-Phase Electricity Theft Based on Multi-Dimensional Feature Extraction.

The advent of smart grids has facilitated data-driven methods for detecting electricity theft, with a preponderance of research efforts focused on user electricity consumption data. The multi-dimensional power state data captured by Advanced Metering Infrastructure (AMI) encompasses rich information, the exploration of which, in relation to electricity usage behaviors, holds immense potential for enhancing the efficiency of theft detection. In light of this, we propose the Catch22-Conv-Transformer method, a multi-dimensional feature extraction-based approach tailored for the detection of anomalous electricity usage patterns. This methodology leverages both the Catch22 feature set and complementary features to extract sequential features, subsequently employing convolutional networks and the Transformer architecture to discern various types of theft behaviors. Our evaluation, utilizing a three-phase power state and daily electricity usage data provided by the State Grid Corporation of China, demonstrates the efficacy of our approach in accurately identifying theft modalities, including evasion, tampering, and data manipulation.

A fast detection method for metering anomalies of three-phase energy meters based on sliding filter and decision tree

In the actual measurement of three-phase electricity meters, the presence of electromagnetic interference, environmental temperature, and other factors increases the noise in the measurement data, which affects the accuracy of anomaly detection. In this regard, a fast detection method for three-phase meter measurement anomalies based on sliding filters and decision trees is studied. Firstly, sliding filtering and sliding window matrix methods are used to reduce the dimensionality and filter the measurement data of three-phase electric meters. Then, a cascaded random forest is constructed using a CART decision tree, and the filtered three-phase meter measurement data is input into the cascaded random forest. The CART decision tree uses a binary method to partition the nodes. Finally, using the Gini coefficient as a measurement indicator, a cascaded structure is formed through layered stacking to output rapid detection results of outliers in three-phase electricity meter measurements. The experimental results show that this method can quickly detect measurement abnormalities of three-phase energy meters, timely detect meter flying anomalies and unexpected mutations, and improve the fault handling efficiency of three-phase energy meters.

Increasing the accuracy of electrical energy accounting at reduced load

The object of research is a three-phase electricity metering unit, which includes a digital meter and measuring current transformers. The reduction of non-technological energy losses is restrained due to the insufficient accuracy of the accounting of electric energy in distribution power networks under a reduced load current of the metering unit. The possibility of representing the dependence of the relative error of electricity measurement on current values by a fuzzy function at reduced load has been confirmed. The boundaries of such a function are approximated with sufficient accuracy by the sum of two exponents, which is explained by its significant nonlinearity in the range of reduced current. The proposed EMRL software allows to estimate the real consumption and the most possible level of underaccounting based on the array of electricity meter readings. The accuracy of estimating by the EMRL the amount of electricity consumed with a probability of 0.7 can be estimated with a relative error not exceeding 2 %. The probability of psychophysical assessments of the accuracy of EMRL «very good» and «good» is at least 0.833. The trend of a significant decrease in the relative value of underaccounting with an increase in the level of electricity consumption was revealed. With a daily consumption of up to 10 kW·h, the amount of underaccounting can reach 18 %, and with a consumption of more than 20 kW·h, it does not exceed 6 %. The adequacy of the results of estimating the amount of consumed electricity at reduced load using the EMRL was confirmed by experimental data at a significance level of 0.05. The software capabilities allow to increase the accuracy of the accounting of electrical energy in distribution networks with a reduced load current of the metering unit. The program can be used as part of automated systems of commercial electricity metering or advanced metering infrastructure to determine the most possible underaccounting due to the operation of metering units at a reduced load

Automated experimental complex on the platform of modern ASCME

Currently, in order to automate and digitalize processes in electrical distribution networks (DEN), ASCME software and hardware systems are widely used, which are mainly designed to solve problems of commercial electricity metering. At the same time, these automated systems do not solve such urgent problems as optimizing the operating modes of distribution networks, operational monitoring of technical and commercial losses of electricity, as well as diagnosing network conditions, including localizing the coordinates of unauthorized withdrawals of electricity (UWE). To date, the National Academy of Sciences of the Kyrgyz Republic and a number of foreign scientific centers have developed the scientific foundations and technologies for solving the above problems in real time. In order to test and study the effectiveness of these new results, it is advisable to create an automated experimental complex (AEC), which is essentially a physical model of ASCME. This is due to the fact that the use of automated information systems currently used in distribution networks for this purpose is practically impossible. This article discusses the general structure, functional tasks and main directions of research using AEC. The complex includes a physical model of the distribution network and the main functional elements of modern automated control and accounting systems for electricity (ASCAE), such as a data concentrator, a computer server, single-phase and three-phase electricity meters and a telecommunications module for transmitting and receiving data. The basis of the special software of the experimental complex is made up of new methods and technologies for solving the above functional problems, which are not included in modern AMR systems. AEC is planned to be used not only for conducting scientific research and experiments, but also for the educational process in technical universities with areas of training in the electrical power industry.

Creation of the Internal Categories for Low-Voltage Three-Phase Electricity Users

Creation of the Internal Categories for Low-Voltage Three-Phase Electricity Users

Standalone portable xenon-129 hyperpolariser for multicentre clinical magnetic resonance imaging of the lungs.

ObjectivesDesign and build a portable xenon-129 (129Xe) hyperpolariser for clinically accessible 129Xe lung MRI.MethodsThe polariser system consists of six main functional components: (i) a laser diode array and optics; (ii) a B0 coil assembly; (iii) an oven containing an optical cell; (iv) NMR and optical spectrometers; (v) a gas-handling manifold; and (vi) a cryostat within a permanent magnet. All components run without external utilities such as compressed air or three-phase electricity, and require just three mains sockets for operation. The system can be manually transported in a lightweight van and rapidly installed on a small estates footprint in a hospital setting.ResultsThe polariser routinely provides polarised 129Xe for routine clinical lung MRI. To test the concept of portability and rapid deployment, it was transported 200 km, installed at a hospital with no previous experience with the technology and 129Xe MR images of a diagnostic quality were acquired the day after system transport and installation.ConclusionThis portable 129Xe hyperpolariser system could form the basis of a cost-effective platform for wider clinical dissemination and multicentre evaluation of 129Xe lung MR imaging.Advances in knowledgeOur work successfully demonstrates the feasibility of multicentre clinical 129Xe MRI with a portable hyperpolariser system.

Wind Turbine Emulator for Wind Power Generation System

This paper proposes the wind turbine emulator for wind power generation systems. The focus is on simulation of the operation of wind turbines at different wind speeds to test the capacity and efficiency of generating three-phase electricity. The wind turbine emulator consists of a simulation program and a mechanical part. To simulate the power generation system of wind turbines, researchers use a 400-watt permanent magnet synchronous generator wind turbine connected to a 400-watt servo motor with a built-in absolute encoder and controlled by a servo driver. The motor's torque is controlled by data from mathematical equations in the MATLAB model.

Electrical Energy Usage on Kansas Grain Farms

Four thousand Kansas agricultural producers were surveyed to determine electrical equipment and energy management practices used for grain, livestock, and dairy production in 1989. Completed questionnaires were obtained from 1177 producers, of which 554 were grain producers. Data from these producers were analyzed to determine types of equipment used for grain production, handling, and processing by geographic location and variables that could be used to predict electrical energy consumption for grain producers. Over 70% of the grain producers reported an average electrical energy consumption of 1395 kWh per month. Less than 20% of these producers used both single- and three-phase electricity on their operation. The most frequently used grain drying system was natural air.

Energy Usage on Kansas Livestock and Dairy Farms

Four thousand Kansas agricultural producers were surveyed to determine electrical equipment and energy management practices used for grain, livestock, and dairy production in 1989. Completed questionnaires were obtained from 1177 producers, of which 519 and 68 were livestock and dairy producers, respectively. Data from these producers were analyzed to determine types of equipment used for livestock and dairy production by geographic location and variables that could be used to predict electrical energy consumption for livestock and dairy producers. Over 70% of the livestock producers reported using an average of 2157 kWh of electricity per month in 1989. Less than 20% of the livestock producers used both single- and three-phase electricity on their operation. Forty-two percent of the swine producers reported using an average of 11 ventilation fans in all swine buildings. An average of one ventilation fan was used per 100 head of swine. Electricity and liquid petroleum gas (LPG) were the most common energy sources used to heat on-farm agricultural facilities.

Testing high-precision three-phase electricity meters

The method of testing high-precision three-phase electricity meters in artificial connections by means of a single reference instrument is satisfactory. This method can also be used for testing multiphase wattmeters.

The cost of electricity at the source

The Stott-Gorsuch method is applied to the determination of the cost of manufacturing electricity in a 60-cycle station of 100,000 kilowatts installed capacity. The results correspond to the assumption that such a station is capable of delivering from 350,000,000 to 700,000,000 kelvins per annum for load factors ranging from 0.50 to 1.00. For unity load factor the cost of three-phase electricity at the outgoing cables ranges from 0.65 cent per kelvin with coal at $5.00 per ton, down to a matter of 0.20 cent per kelvin for fuel of negligible cost. A method is indicated for tracing through the increase in the cost of the electricity at later stages of its journey from the source to the consumer.

The Cost of Electricity at the Source

The Stott-Gorsuch method is applied to the determination of the cost of manufacturing electricity in a 60-cycle station of 100,000 kilowatts installed capacity. The results correspond to the assumption that such a station is capable of delivering from 350,000,000 to 700,000,000 kelvins per annum for load factors ranging from 0.50 to 1.00. For unity load factor the cost of three-phase electricity at the outgoing cables ranges from 0.65 cent per kelvin with coal at $5.00 per ton, down to a matter of 0.20 cent per kelvin for fuel of negligible cost. A method is indicated for tracing through the increase in the cost of the electricity at later stages of its journey from the source to the consumer.