Development Of Power System Research Articles

Teaching Power-Sector Models Social and Political Awareness

Energy-system scenarios are widely used to relate the developments of the energy supply and the resulting carbon-emission pathways to political measures. To enable scenario analyses that adequately capture the variability of renewable-energy resources, a specialised type of power-sector model (PSM) has been developed since the beginning of this century, which uses input data with hourly resolution at the national or subnational levels. These models focus on techno-economic-system optimisation, which needs to be complemented with expert socioeconomic knowledge in order to prevent solutions that may be socially inacceptable or that oppose political goals. A way to integrate such knowledge into energy-system analysis is to use information from framework scenarios with a suitable geographical and technological focus. We propose a novel methodology to link framework scenarios to a PSM by applying complexity-management methods that enable a flexible choice of base scenarios that are tailored to suit different research questions. We explain the methodology, and we illustrate it in a case study that analyses the influence of the socioeconomic development on the European power-system transition until 2050 by linking the power-sector model, REMix (renewable-energy mix), to regional framework scenarios. The suggested approach proves suitable for this purpose, and it enables a clearer link between the impact of political measures and the power-system development.

TEST BENCH EQUIPMENT OF KELDYSH RESEARCH CENTRE FOR TESTING HIGH-PERFORMANCE POWER AND PROPULSION SYSTEMS

Expanding space exploration in near-Earth space and deep space calls for an increase in power supply of space vehicles to a level of hundreds of kilowatts and higher. Pre-requisite for successful implementation of works on development of power propulsion systems of such power level, including those with nuclear energy sources, is availability of a full-scale experimental test bench equipment. A unique experimental test bench has been built and is successfully operating at JSC «Keldysh Research Center», which allows performing both research and developmental tests of key components of high-performance power and propulsion systems under conditions close to nominal operating conditions. The article describes the main components of JSC «Keldysh Research Center» test bench equipment, presents some results of the work fulfilled on it, outlines prospects for its furtherance and use in development of space high-performance power and propulsion systems. Key words: testing, ground developmental testing, power conversion system, test bench equipment, electric propulsion, power and propulsion system.

Power Flow Optimization and Economic Analysis Based on High Voltage Phase Shifting Transformer

With the development of power systems, the power flow problem of transmission line is becoming more and more prominent. This paper presents a power flow regulation method based on phase shifting transformer (PST). Firstly, the working principle and performance of PST are analyzed. Then, the simulation model of BPA multi node system is established. PST access reduces the line imbalance to less than 8%. On this basis, considering the influence of saturation effect and leakage reactance, a PST suitable for 220 kV power grid is designed. Three different working conditions are simulated by PSCAD software. Under normal working conditions and N-1 conditions, PST can increase the transmission limit of the ring network section by more than 20%. When a short-circuit fault occurs, PST can also suppress the fault current. For 220 kV practical projects, unified power flow controller (UPFC) has faster response speed and stronger performance, but PST is more economical and reliable, and the equipment cost is 49.86% lower than that of UPFC. The power flow regulation method based on PST has good steady-state effect. It can improve the utilization efficiency of power grid assets and optimize the power flow distribution in a short time and at low cost.

Analysis of Circuit Parameters of New Graphene Partial Discharge Sensor Electrode Plate Based on Transmission Line Model

Partial discharge (PD) sensors have been widely used in PD detection of power equipment. In order to adapt to the development of the new power system, the new PD sensor should not only have a wide response band but also have a large dynamic range. PD measurement devices currently used in smart grids are mainly based on traditional metal materials, which face difficulty in fully meeting these technical requirements. Graphene has a variety of excellent properties, and it is introduced to improve PD sensor materials in this paper. Based on the transmission line model, the circuit parameters of graphene PD sensor electrode plate material are theoretically derived. Various factors affecting its resistance characteristics, inductance characteristics, and capacitance characteristics are analyzed. Next, the variation curves of circuit parameters under different influencing factors are obtained. Linear regression models based on the least-square method were developed for circuit parameters. Finally, the simulation and experiment verified that the graphene PD sensor has high gain characteristics. The simulation results are consistent with the experimental results, further verifying the feasibility of the circuit parameter study. This study can be used to guide the design of the new graphene PD sensors.

Power Grid Low Carbon Collaborative Planning Method Using Improved Cat Swarm Optimization Algorithm in Edge Cloud Computing Environment

The current power grid planning mostly realizes the calculation and analysis based on the factors of operation reliability or operation economy, but low-carbon green operation has become the main melody of power system development. Aiming to support the green and reliable operation of the power grid, this paper proposes a power grid low-carbon collaborative planning method based on improved cat swarm optimization algorithm. First, the carbon emission characteristics of the whole cycle of power grid construction are analyzed on the edge side, and a power grid planning model including environmental, economic, and reliability is constructed; on the cloud side, the cat swarm optimization algorithm is improved based on quantum mechanics and chaotic algorithm to achieve efficient solution to the power grid low-carbon planning model, which can support the stable and sustainable operation. Finally, the simulation experiment is realized based on IEEE 39 bus system. In this experiment, the construction cost and carbon emission of the proposed collaborative planning method are 23 million yuan and 2.28 t/MWh, respectively, which can reduce carbon emission while optimizing the construction cost and maintaining the low-carbon and stable operation.

A Novel DC Circuit Breaker with Fast Breaking Capability in Full Current Range

With the rapid development of DC power system in recent years, more stringent requirements have been put forward for the rapid reliability of DC circuit breakers. At present, most hybrid circuit breakers widely used create artificial zero crossing by injecting current opposite to short-circuit current. However, when it comes to the small current, the injected current may reverse puncture the contacts of the high-speed mechanical switch. And this results in the difficulty of extinguishing the arc between the contacts of the high-speed mechanical switch during disconnection, prolonging the disconnection time and adversely affecting the system. This paper presents a double break DC circuit breaker structure based on double capacitor structure. In the process of current breaking, the capacitor with small capacitance is used to commutate for small current, and the double capacitor parallel method is used to complete the current transfer for large current. The working principle of the circuit breaker is analysed, and the appropriate parameters are selected through simulation.

Hybrid DC Circuit Breaker with Integrated Self-charging and Current Limiting

With the rapid development of DC power systems in recent years, more stringent requirements have been put forward for the fast reliability of DC circuit breakers. At present, in the medium voltage DC circuit breaker, the mechanical switch commonly uses an external secondary power supply to charge the mechanism drive capacitor, which has the problems of large breaker size and high cost. In this paper, we propose a DC circuit breaker topology that uses short-circuit current to charge the mechanism drive capacitor of the mechanical switch. When the short-circuit current rises, a voltage drop is formed across the series inductor, and this voltage charges the drive capacitor in parallel through a diode, avoiding the use of a secondary power supply to charge the drive capacitor and reducing the complexity of the DC circuit breaker system. The operating principle of the circuit breaker is analysed and the rationality of the proposed scheme is verified by simulation calculations.

Machine Learning and Data Mining Applications in Power Systems

This Special Issue was intended as a forum to advance research and apply machine-learning and data-mining methods in order to facilitate the development of modern electric power systems, grids and devices, smart grids and protection devices, as well as to develop tools for more accurate and efficient power system analysis [...]

Design and Development of Power and Time Control System of Various Color Laser as a Beauty Therapy Application

Design and Development of Power and Time Control System of Various Color Laser as a Beauty Therapy Application

Environmental efficiency assessment of China’s integrated power system under the assumption of semi-disposability

As the largest terminal carbon emitter in China, power industry is crucial for achieving carbon peak by 2030 and carbon neutrality by 2060, and constructing a sustainable society. To scientifically evaluate the environmental efficiencies of the regional power system, this study proposes a modified dynamic network slacks-based measure (DNSBM) model based on semi-disposability. It investigates the effects of the new round of power system reform by measuring the environmental efficiency of China’s 30 provincial administrative regions’ power system from 2014 to 2017. The results show the following: (1) The semi-disposability assumption performs better in objectivity and gauging the performance of decision-making units than the weak or strong disposability assumptions. (2) The ratio of renewable energy is positively correlated with the environmental efficiency and its decomposition indicators. Furthermore, the establishment of the power market helps to improve the environmental efficiency of the power system. (3) The new round of power system reform launched in 2015 has significantly improved the efficiencies of generation and distribution divisions. However, the efficiency of the transmission division changes slightly due to the heterogeneity of factors affecting the development of the regional power system.

An economic and spatial analysis of the development of the infrastructure electric power system of the Ural Macro-region

Subject. This article considers the organizational and economic relations arising in the process of development of the electric power system of a macro-region. Objectives. The article aims to analyze trends in the development of the electric power system of the Ural macro-region. Methods. For the study, I used analysis, synthesis, and generalization. Results. The article presents spatial structure and composition of the electric power system of the Ural macro-region. It shows high differentiation and multidirectionality of electricity consumption, production and availability within the macro-region. Conclusions. The spatial structure of the electric power industry of the Ural macro-region is heterogeneous in a number of parameters. This affects the strategic planning, and setting goals and objectives. It is necessary to develop mechanisms and tools to ensure a balanced development of the constituent entities of the Russian Federation.

Allocation of Energy Storage Capacity Based on Optimal Power Flow

Under the continuous development of new power system, the double high characteristics become more and more obvious in the characteristics of power system. How to make good use of electrochemical energy storage and participate in the power market has become an urgent problem to be solved. In view of this, based on the day ahead market forecast,this paper establishes a model for the participation of electrochemical energy storage in the operation of the electricity market and sets up three different scenarios with the goal of maximizing gross profit. Finally, it is concluded that the operation strategy of electrochemical energy storage proposed in this paper can effectively improve the benefits of electrochemical energy storage.

Development of a Compound Power-split Hybrid Power System for Commercial Vehicles

Development of a Compound Power-split Hybrid Power System for Commercial Vehicles

Valence Engineering of Polyvalent Cobalt Encapsulated in a Carbon Nanofiber as an Efficient Trifunctional Electrocatalyst for the Zn-Air Battery and Overall Water Splitting.

The rapid development of electrochemical power systems has prompted high demand for nonprecious trifunctional electrocatalysts with superior performance, prolonged stability, and low cost for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). Here, a valence engineering strategy is devised to construct a morphology with polyvalent cobalt encapsulated in nitrogen-doped carbon nanofibers (Co/N-CNFs). The diverse cobalt valence states of the Co/N-CNF catalysts contribute to their excellent catalytic effect and high durability in multiple electrochemical processes. The optimal Co/N-CNF catalyst fabricated exhibits a high half-wave potential of ORR (0.86 V) and low overpotentials of OER (380 mV) and HER (241 mV) at 10 mA cm-2. The Co/N-CNF-based Zn-air battery possesses a high charge-discharge efficiency as well as a good cycle stability (50 h at 10 mA cm-2 and 120 h at 20 mA cm-2), much superior to the Pt/C-based batteries. Furthermore, the Co/N-CNF catalyst could perform efficient overall water splitting.

Analysis and Simulation Research of Cascading Faults in AC/DC Hybrid Grid

In the development of power systems, the traditional AC power grids are gradually evolving into AC/DC hybrid grids. However, the safety of hybrid grids is threatened by cascading faults, which is a set of chain events caused by a single fault and will eventually lead to a blackout. Based on the blackout accident that happened in Brazil on March 21st, 2018, this paper analyzes the cause, mechanism, and development of cascading faults in AC/DC hybrid grids. Simulations based on PSCAD/EMTDC software have been carried out to illustrate the typical cascading fault scenario including HVDC commutation failure, DC blocking, power flow transferring, incorrect relay protection and the outage of the network. Both analysis and simulation results shows that the “strong DC weak AC” structure and unreasonable cooperation of relay protections and stability control devices are important factors of cascading faults. Finally, this paper prospects a series of protection and control technologies that are expected to solve the problem.

The Accelerate Estimation Method of Power System Parameters in Static and Dynamic Processes

Current trends in power system development and the issues they pose have increased the urgency of automatic and emergency control alongside transient electromechanical processes. Such control devices place high demands on mode-parameter estimation algorithms in terms of their speed, accuracy, and transient sensitivity. This paper proposes a rapid estimation algorithm for power system parameters to investigate its optimal settings and applicability in both static and dynamic states. The proposed algorithm is based on signal approximation on a sliding window using a multiparameter model, which is highly stable and reliable. The signals modeled in MATLAB/Simulink were used as initial data. From the experimental results, it became clear that the rapid estimation algorithm of the power system parameters showed high accuracy in steady-state mode as well as during transients, and its optimal parameters were identified. The developed algorithm can be used in relay protection, automatic and emergency control devices, and synchronous machine state-monitoring systems.

Expected Failure Method and Its Analysis for Safety Evaluation in a Cyber-Physical Power System

With the development of communication technology, power and information systems have become deeply coupled and have become the most massive and complex cyber-physical power systems (CPPSs), resulting in certain risks to the safe operation of power systems. In this paper, a CPPS security assessment method based on the expected failure method and considering combined information attacks is proposed. Due to the large number of nodes in modern information systems, enumerating all possible combinations of system failures for evaluation and analysis is unrealistic. By considering the topological relationship of the CPPS and the electrical properties of coupled physical nodes, the idea of first screening information nodes is proposed in this paper to filter the information nodes. The impact of combined information attacks on the expected physical fault handling process is analyzed, and a safety evaluation index for the distribution network is provided. In addition, the proposed method is applied to the IEEE-118 system and compared with previous evaluation methods to verify its effectiveness.

A Review on TSO-DSO Data Exchange, CIM Extensions and Interoperability Aspects

The exchange of information between transmission system operators (TSOs) and distribution system operators (DSOs) is a common practice. However, the evolution of the regulatory frameworks in Europe has increased the need for enhancing TSO-DSO data exchange and interoperability. This paper provides an overview of the TSO-DSO data exchanges and demonstrates the best practices using International Electrotechnical Commission (IEC) common information model (CIM), including the implementation of IEC common grid model exchange standard (CGMES), and discussion of the corresponding advantages, disadvantages, and challenges. Furthermore, this paper evaluates and reports the activities already carried out within European projects, with particular focus on TSODSO interoperability. Finally, this paper concludes the need for TSOs and DSOs to rely on standard-based solutions when performing TSO-DSO data exchange, which enables the efficient operation and development of the future power systems.

Fuzzy-TOPSIS Evaluation of Power Product-Service System: A Framework Driven by Big Data

Power product-service system (power PSS), which combines industrial electric products with electric energy services, is an effective solution for power enterprises under the background of the rapid development of power systems. In the life cycle of power PSS, evaluation decision of power PSS alternatives is of great significance for subsequent implementation. To address the power PSS alternative evaluation problem, a power PSS evaluation framework is explored driven by the big data of stakeholder comments. Based on the multi-stakeholder comments of power PSS evaluation decision’s influence factors, the index system is constructed through analyzing and summarizing the co-occurrence matrix and semantic network diagram of high-frequency words. To determine the fuzzy index value of power PSS alternative, the stakeholders’ vague opinions expressed by trapezoidal fuzzy number are integrated by group decision method. Fuzzy concept is introduced into the classical Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) method and fuzzy-TOPSIS method is put forward by using the fuzzy index value. The improved TOPSIS is adopted to sequence the power PSS alternatives. The case of power PSS evaluation of six alternatives for a power enterprise shows that the explored framework is effective and can provide a feasible solution for power PSS alternative evaluation.

Scenarios for future power system development in Finland

This paper demonstrates how various part-solutions can be combined in different scenarios for a more climate-neutral electric energy system. The case study is the Finnish electric energy system. Four scenarios are discussed. A base scenario for 2030 consists of already agreed future investments in new energy production facilities by 2022 supplemented by additional consumption and a moderate increase in renewable energy generation. Alongside the base scenario 2030, two scenarios with more ambitious renewable energy targets and flexibility issues are examined. The fourth scenario is for year 2050 analyzing the operational properties of the system with high share of variable renewable generation, flexible loads, and high-capacity energy storages. These scenarios help to assess how, for example, investing in wind or solar production, heat pumps on a large scale or the battery storage of electric vehicles influences the other components of the system and the implications for emissions.