Power Network Equipment Research Articles

Trends of Asset Management Techniques for Electric Power Network Equipment

Trends of Asset Management Techniques for Electric Power Network Equipment

Research on Fault Prediction and Health Management System of Power Electronic Devices Based on Computer Deep Learning Algorithm

This paper proposes a power equipment maintenance management system based on network and deep learning algorithm. First of all, the actual power network equipment maintenance and maintenance management of the power company, so as to clarify the tasks to be completed by the system. ASPNET technology is used to realize the management of business form data and various transaction processes of each system, and the related technology of process engine is applied to the maintenance of each equipment. A load forecasting method of power system based on SVR is proposed. It makes the operation and maintenance work of this system more intelligent. Each function module of the whole system is designed in detail. The system basically meets the needs of power equipment maintenance and repair management.

Research on Illegal Mobile Device Identification Based on Radio Frequency Fingerprint Feature

Internet of Things (IoT) technology is widely used in new power systems, and it also provides many new modes for network attacks. Illegal terminal device identification is also a significant topic in the field of wireless authentication technology. Some kinds of power network equipment are located in sparsely populated areas and rely on IoT terminals for real-time monitoring. Attackers use illegal terminals to connect power IoT devices for production monitoring and to carry out network attacks, which may cause serious damage, such as power data theft and misoperation of power network equipment. Radio frequency fingerprint (RFF) can extract hardware features from different devices, and is widely used for device identification and authentication. The area over which power network equipment placed is vast, and there are many wireless communication devices and terminals. It is difficult to identify illegal devices through commonly used network management techniques, thus making it difficult to distinguish between the mobile terminals of employees and illegal terminals in general spectrum screening. In response to the above situation, this paper uses the characteristics of the squared spectrum of random access preamble signals to extract hardware device features, proposes an illegal device identification algorithm based on Gaussian distribution theory, and evaluates its performance. The experimental results show that, when the signal-to-noise ratio (SNR) is greater than 15 dB, the average recognition result is greater than 92%. In addition, the algorithm has low computational complexity and high engineering application value.

Эко-НИОКР – 18 лет для охраны птиц на объектах электросетевого комплекса России

Эко-НИОКР – 18 лет для охраны птиц на объектах электросетевого комплекса России

Estimation of acceptable failure rates for equipment of power distribution network

Regulatory requirements for reliability indexes of power distribution networks are considered. The dynamics and structure of the reliability indexes of electricity distribution companies are analyzed. Criteria for determining the acceptable number of outages of power network equipment are proposed to calculate the acceptable frequency of outages. The proposed approach is illustrated by calculation of acceptable values of reliability indexes for the power distribution network of Moscow Region.

Power network-planning optimization considering average power not supplied reliability index: Modified by chance-constrained programming

In this paper, a mixed-integer linear formulation for optimization multi-stage power system is represented. In order to achieve the best results, all facilities should be considered simultaneously due to the interconnection between power network equipment. In this paper, power plant, HV and MV substations and Distributed Generation (DG) are regarded concurrently to create an integrated power system planning. Furthermore, a reliability index called Average Power Not Supplied (APNS) in load point is modelled. Stochastic programming in the Chance-Constrained approach is also utilized to overcome uncertain parameters containing demand in load points, nominal voltages and facility failure rates. The mathematical model is tested on a real life case study in four schemes containing with or without considering DG and in certain or uncertain environment. Using both DG and MV substation in schemes planning leads to the establishment of a parallel system to improve network reliability. Since each scheme has specific requirements, it’s mathematical formulation is discussed in detail. The proposed formulation determines the optimum system configuration, including feeder routing, siting and sizing for power plant, HV/MV substation and DG. The numerical results show that planning in uncertain environment has a higher cost in comparison with certain model, but the results are more close to real world operations. Based on the obtained results a planner can estimate the cost components in different environments. Also in uncertain schemes, the growth in confidence levels increases the grid total cost. Therefore, planners must create an appropriate balance between confidence level and system total cost. Numerical results suggest that using DGs leads to a decrease in the required substations, their power to service load points and APNS cost. Thus using DGs can be an economic alternative to decrease system total cost. The achieved results indicate that the proposed planning for designing a power network has a desirable performance in practice.

Calculating the sequence of stationary modes in power distribution networks of Russia for wide-scale integration of renewable energy based installations

The global trend of the past decades on the development of the decentralized power generation concept is associated with the growing number of power plants integrated into power distribution networks including those employing renewable energy sources. In recent years, high-capacity wind power and solar PV stations have been put into operation, in Russia, and wide-scale construction of micro-generation sites is at the stage of planning and design. Under these conditions, power distribution networks will be permanently affected by the deviation of operational status that can be indicated in the temporary change of stationary mode parameters. Currently it is not technically possible to equip all network control and supervision Centers with hardware and software complexes designed to calculate automatically transients in operation modes in order to work out decisions on prompt actions for controlling network operational status and maintaining its operation modes within the range of permissible values of their rated parameters. In this article, the principles have been analyzed that enable to apply the existing software complexes for calculating the sequences of stationary operating modes (SSOP). Results of calculating SSOP make it possible to perform the analysis of changes that may occur in power distribution, in transient conditions, and to work up reasonable control actions in order to stabilize operation modes of power network equipment. Properly estimated amount of available reactive capacity of generating installations helps to prevent critical voltage drop in load nods, as well as occurrence of voltage avalanche, in installations, particularly in industrial power consuming areas. In power distribution networks, operating mode characteristics essentially depend on parameters of loads due to their comparability with the aggregate capacity of generating installations and low interaction impedance. The issues of accurate load modeling and those of possible assumptions have been considered. The principles of application of the results of SSOP calculations for the analysis of the effect of voltage control devices, in live conditions, automatic voltage control equipment and quick-response shunt compensation devices that make their contribution in VAR flow and distribution power network operation have been demonstrated.

Temperature self-regulating electrothermal pseudo-slippery surface for anti-icing

Ice accretion has become an urgent problem and considerably decreases the reliability of aerospace, power network, and transportation equipment. Herein, a temperature self-regulating electrothermal pseudo-slippery surface with intelligent anti-icing ability was introduced by combining electrothermal effect and phase transition lubricant, which exhibits positive temperature coefficient (PTC) effect and interfacial state switching performance. The coating exerts its PTC effect to realize smart temperature accommodation, and automatically regulates its EPD for anti-icing under various cold loads, greatly decreasing the energy consumption of anti-icing by ~ 30% at an initial electric power density of 1.5 W/cm2 (compared with general electrothermal coating) and preventing overheating even at an initial electric power density of 5 W/cm2 without requiring complex regulatory equipment. After heating, the reversible solid to liquid phase transition of the lubricant assisted the switch from pseudo-slippage to slippage of the surface, decreasing ice accretion on the coating (by ~ 40% after icing for 120 s at –40 ± 3 °C). Furthermore, the mechanical function of PTC–ESS was highly stable in continuous humid airflow/sand scour tests. The integration strategy will provide inspiration for designing intelligent anti-icing surfaces and promote their engineering applications.

Research on control strategy of MMC DC power electronic transformer based on DAB mode

High-power DC power electronic transformer (DC PET) is becoming the key equipment in the DC power network. Face-to-Face (F2F) DC transformers based on modular multilevel converter (MMC) have the modular structure and can flexibly design systems based on different voltage and power levels. Previous studies show that the control strategy of the F2F topology regulates the MMCs separately. Moreover, the voltage ratio of the DC sides depends on the intermediate AC transformer. In the current study, a new control strategy is proposed, which can change the DC voltage ratio by turning on/off submodules of each MMC bridge flexibly and set relevant parameters with different application scenarios. The algorithm enables the DC PET with F2F topology to operate in a dual active bridge (DAB) circuit mode. Thereby reducing the overall system size and meeting different demands of medium and high voltage application scenarios. According to the control strategy used, a submodule capacitor voltage equalization method is proposed to eliminate the capacitance voltage deviation and reduce the capacitance voltage stress. At the same time, the current characteristics of the AC conversion part in the DC transformer are analyzed. Finally, the feasibility of the proposed method is verified by simulation and experiments.

Design of patrol and control platform for power network based on UAV and VR

Since the beginning of the twenty-one th century, with the rapid development of China’s economy and the continuous progress of China’s power industry, it has contributed an indelible force to the development of China’s socialist undertakings The construction of power grid is very important to the development of society. The normal operation of the power grid can not be separated from regular inspection of power grid equipment and lines, so as to keep abreast of and understand the operation of power transmission lines and changes in the surrounding environment and Line Protection Areas Is the power supply enterprise a heavy daily work. Manual inspection is a traditional inspection method, but also the main way of transmission line inspection. Due to the complex terrain of the transmission line corridor, there are almost no patrol roads in some sections along the route in some harsh conditions such as river-crossing or high mountains and steep mountains. This patrol method has great labor intensity and difficult working conditions Transmission lines can not get timely feedback, and can not observe the real-time intuitive operation of lines and equipment. In this case, in response to the national “Internet +” strategic thinking, we initiated the “Internet +”, “UAV +” and “VR +” all-ecological power grid patrol mode Realize the power network equipment long-distance inspection, all-round inspection, real-time simulation inspection, inspection in bad environment, so that the cause of power inspection can take off.

Evaluation of Online Techniques Utilized for Extracting the Transformer Transfer Function

Power transformers have vital importance in the power delivery and, therefore, different diagnostic techniques are proposed for them. The frequency response analysis (FRA) is an effective method which detects the mechanical changes in transformer windings by extracting the transfer function. There are various approaches for obtaining the transfer function online, which is known as the online FRA technique. This paper compares these different mathematical approaches for obtaining the transfer function of a transformer. The comparison is carried out by defining an appropriate model for the transformer and applying these mathematical methods to it. The effect of other power network equipment on the transformer transfer function is also studied in this paper. The results of this contribution determine the proper methods for the online FRA technique, which can be used in the transformer monitoring applications.

AC Loss Analysis of a Single-Solenoid HTS SMES Based on H-formulation

There will be much AC loss generated when a superconducting magnetic energy storage(SMES) is applied in a power system to exchange power with a power network or other equipment. AC loss may cause the instability and risk of burnout to SMES. This paper presents a commonly used SMES design scheme and lists the design parameters of a 10MJ/5MW SMES. We used the finite element software COMSOL to build a simulation model to calculate the AC loss during its operation. We get the calculated results and analyse AC loss`s distribution characteristics of the 10MJ/5MW SMES which uses a single screw structure.

Analysis of causes of failures in 10 kV electrical power distribution networks (on the example of the Southern electrical networks of the city of Irkutsk)

Disconnection of power consumers from power grids is quite a common event, with a wide range of consequences. Power supply interruptions can be caused by both casual events, and planned shutdowns. Disruptions in systems of power supply of consumers lead to a variety of adverse events (under-delivery of products, large-scale product rejection, failure of production equipment, etc.), which inflicts a significant economic damage. The retrospective analysis of the failure rate of electrical networks of the Right Bank and Left Bank districts of Irkutsk over 2013–2017 has been carried out. The analysis was based on the data from dispatching logs of observations on events of failures caused by emergency damage to the Southern electrical networks. It is established that the greatest number of failures occurs for such reasons as damage at substations, damage to consumer electrical networks, wire breakage in air and cable power lines as well as damage of switching equipment. Failures related to wind load, damage at packaged transformer substations, insulators and surge arresters are also analysed. The percentage rate of failures of electrical power networks caused by specific reasons from the total number of failures is presented. Besides, the analysis is performed of the duration of interruptions of power supply owing to damage of individual elements of power network equipment as well as the amount of electric energy undelivered for these reasons, and financial losses caused by these failures due to under-delivery of electric energy, with the average wholesale electricity prices taken into account.

Research on transformer fault diagnosis method and calculation model by using fuzzy data fusion in multi-sensor detection system

In order to achieve the failure of unattended power network equipment, this paper proposes a new transformer fault diagnosis method by using multi band infrared imager sensor and discharge circuit detection sensor to set up the eight sensors detection platform. Analyzes the transformer fuzzy fault characteristics, designs the detection platform of transformer fault diagnosis, establishes a transformer fuzzy fault diagnosis model with the exponential trust function of the photoelectric sensor, the average weighted consistency of each photoelectric sensor and the support degree of the photoelectric sensors, gives the data fusion method with the trust function of the sensor and the maximum model value. Through experiment and analysis, this fault diagnosis model can improve the fusion precision and diagnostic accuracy more effectively than the general fusion algorithm and arithmetic mean value algorithm, and can scientifically diagnose the transformer equipment of power grid from multi angle. Thereby, the feasibility and effectiveness of the method are verified.

Flashover and Back-Flashover Analysis with Lightning Strokes of 69 kV and 24 kV Lines in Thailand Using ATP/EMTP

Lightning is the principal source of disturbance in power system leading towards outages and damage of expensive equipment in the electrical power network. Induction of disastrous voltages across string insulators from the lightning that causes flashovers and back flashovers have been the major study in recent researches. Efficient parameterization of lightning and it is associated with behavior provides a significant knowledge towards successful operation of the electrical network. Therefore, this work studies the effects of flashover and back flashover affected by negative lightning (single and double) strokes in the operation of 69 kV sub-transmission line and 24kV distribution line of Metropolitan Electricity Authority, Thailand. Seven poles spanning 24 km were considered in this study. Lightning was initiated at the vertex of the fourth pole and mid-span of the third and fourth pole, and investigations were carried out by lightning magnitude and multiplicity when it hits an overhead ground wire (OHGW) and phase A of the 69 kV line by using ATPDraw. Results showed that negative lightning stroke of -34 kA and above could induce disastrous voltages across string insulators that leads to back flashover and flashover when hits at the top and mid-span of OHGW and phase conductor respectively. Power failure in 69 kV may cause double failure to the network since it is the main power source of 24 kV line. Consequently, a double failure may direct towards reduced reliability and extra maintenance cost of catastrophically damaged line insulators. Therefore, the concept of flashover and back-flashover can help to improve the lightning performance of MEA power lines.

MODERN INFORMATION TECHNOLOGIES IN THE CONTROL SYSTEMS FOR COMPLEX BIOTECHNICAL OBJECTS OF AGRICULTURAL APPOINTMENT

Background. In modern world, the tasks of forming appropriate control strategies for various biotechnical objects of agricultural purpose are aimed at minimizing energy costs. Traditional control systems for complex biotechnical objects in conditions of high energy costs are inefficient. It is proposed to develop energy-efficient intelligent control systems using, as a criterion of efficiency, enterprise profits and modern information technologies. Objective. The aim of the paper is the creation of energy efficient intelligent control systems based on the analysis of natural disturbances, biological component states, price policy, continuous monitoring of the power grid equipment operation mode parameters’ stability. Methods. The analysis of existing traditional control systems for complex biotechnical objects in conditions of high energy cost made it possible to identify effective solutions for improving the reliability of integrated power supply systems for the agro-industrial complex and developing energy-efficient control systems for complex biotechnical objects. Results. The solution to the problem of minimizing energy costs has been obtained, which contributes to an increase in the production profit in general, due to the formation of appropriate control strategies for electrical facilities that are components of technological equipment. Conclusions. The modern theory of automatic control makes it possible to develop, using information technologies, energy-efficient control systems for complex biotechnical objects on the basis of analysis of natural disturbances, states of the biological component, price policy in the market of marketable products, and continuous monitoring of the power network equipment operation mode parameters’ stability. Keywords: automatic; infocommunication; energy efficiency; electrotechnics; control; synchronization; monitoring.

Fault Analysis for Power Network Equipment Based On Association Rule Clustering Algorithm

In order to improve the fault positioning accuracy of distributed generation power distribution network, it puts forward fault positioning method of distribution network equipment based on blended data association rule data mining method. Based on fuzzy rough set theory, it studies classification rule mining method on hybrid data, through the introduction of the rule to obtain the a generalized threshold of the algorithm, and control the scale and complexity of the obtained rule set, so as to improve the classification efficiency of rough set method of knowledge discovery on the failure data and get the fault positioning feature of distribution network, finally adopts the support vector machine (SVM) to make fault classification, and tests the performance of the algorithm with simulation experiment. The simulation results show that, this paper can be quickly and accurately to locate fault power section, and the fault positioning accuracy is higher than other fault positioning methods of distribution network.

A contribution to the study of the compressive behavior of atmospheric ice

In the last decades, research on atmospheric icing of structures such as power transmission lines has attracted much interest. Accumulation and the shedding of atmospheric ice from overhead transmission lines and ground wires may cause their rupture and tower collapses, leading to power outages.The present work concerns a study of the compressive strength of atmospheric ice, under different experimental conditions such as strain rate, temperature, and porosity. For this reason, ice was accumulated in the closed loop wind tunnel at CIGELE (Industrial Chair on Atmospheric Icing of Power Network Equipment), under three temperatures (−20, −15 and −5°C). The wind speed inside the tunnel was set at 20m/s in order to obtain a mean volume droplet diameter (MVD) of 40μm and a liquid water content (LWC) of 2.5g/m3. Each type of ice was tested at the same temperature at which it had been accumulated. A tomographic analysis was carried out on a small specimen (cylinder of 1cm diameter×2cm length) for each temperature in order to quantify the porosity and determine the grain size and their distribution.The obtained results show a strong dependence of the compressive strength on temperature, strain rate and porosity. The ductile–brittle transition was identified within a strain rate ranging between 10−4s−1 and 10−3s−1. It was found that compressive strength increases with decreasing temperature for deaerated ice. However, for atmospheric porous ice, compressive strength increases until −15°C, then decreases for lower temperatures. Compressive strength of atmospheric ice is highly dependent on porosity, which is related to the amount, size and distribution of pores inside the ice.

Contributory provision point contracts – a risk-free mechanism for hedging cloud energy costs

Cloud computing services rely on electricity to power compute-servers, network equipment, cooling systems, and other supporting infrastructure. As such, energy costs are a substantial outgoing to public providers of cloud computing services. On-demand pricing, where consumers are not required to give advance notice of requirements, does not aid the provider in planning future demand, and therefore makes it more difficult to purchase energy at discounted rates. In this paper, we propose an advance pricing mechanism for cloud computing resources based on provision-point contracts, commonly used by deal-of-the-day websites such as Groupon. We show how our Contributory Provision Point (CPP) contracts reward consumers with reduced prices for advance reservations, while allowing providers to make accurate forecasts of energy usage. We show how CPP contracts are risk-free for the provider, guaranteeing to be at least as profitable as on-demand mechanisms where electricity is purchased ad-hoc by the provider. Through a computer simulation, we demonstrate that CPP contracts can be more profitable for the provider compared to a traditional method of hedging electricity futures using a popular forecasting algorithm. Furthermore, we show that CPP contracts encourage consumers to forecast honestly by rewarding them with discounted rates, while remaining profitable for the provider, even when forecasts are not completely accurate.

Effect of Different Aluminium Surface Treatments on Ice Adhesion Strength

Excessive ice accumulation on power network equipment can affect their integrity and cause damage with serious socioeconomic consequences. To mitigate that, de-icing techniques (mechanical or thermal) have been developed, but these techniques are often limited in their application and are generally expensive and time consuming. Recently, companies and research groups have focused on the development and application of icephobic coatings such as superhydrophobic materials intended to drastically reduce ice adhesion force on exposed equipments. The aim of this paper is the examine the influence of aluminium surface treatments on ice adhesion. Preparation of new and various aluminium surface treatments as well as the need to improve the knowledge of the mechanisms involved in ice adhesion are part of this research. Depending of the type of materials, surface roughness can either promote the formation of air pockets within pores or between coating surface asperities (low adhesion strength), or it can create ice mechanical anchoring if water partially or totally penetrates the porosity. Aluminium anodization using phosphoric acid was studied. Surface morphology was evaluated using scanning electron microscopy and measurements of ice adhesion strength were performed using a centrifuge technique. Based on these results, several surface treatments of aluminium have been considered including aluminium anodizing with partial Al2O3 etching followed by different sealing steps using hydrophobic polymer compounds such as polytetrafluoroethylene.