Electric Power

Renewable Energy Capacity Assessment in Power System Based on Linearized OPF

DONG Yu, DONG Cun, YU Ruoying, DING Jie

2022, 55(3): 1-8. DOI: 10.11930/j.issn.1004-9649.202107061

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With the deepening adjustment of energy structure, the penetration of renewable energy in power system is gradually increased. The fluctuation and randomness of renewable energy output have brought new challenges to the power system operation. It is of great significance for the planning and operation of power system with renewable energy to scientifically evaluate the capacity of renewable energy consumption. In this paper, a linear optimal power flow (OPF) model of renewable energy consumption capacity in power system was established. Considering the nonlinear characteristic of power system power flow, a linearization method was established to solve the problem that the traditional high-order nonconvex OPF model is difficult to obtain the global optimal solution. Considering the voltage magnitude, line power flow, power injection and the climbing constraints, the renewable energy consumption capacity of power system was evaluated. The effectiveness of the proposed OPF is verified by simulation analysis, and the main factors restricting renewable energy penetration are discussed with a standard testing system.

High-Frequency Resonance Evaluation and Suppression Measures for Receiving-End of Kun-Liu-Long DC Project

XU Panteng, ZHU Bo, YU Wenxiang, SONG Shubo, YANG Xueguang, FAN Youping

2022, 55(3): 9-17. DOI: 10.11930/j.issn.1004-9649.202103129

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The voltage source converter is prone to negative damping in the high-frequency harmonic band, thus causing resonance phenomena. The Kun-Liu-Long DC project, as a UHV multi-terminal hybrid DC transmission project, needs to evaluate and analyse the high-frequency harmonic resonance risk of its flexible DC converter stations in Liuzhou and Longmen. Based on the impedance analysis method, an analysis is made of the impact of control link delay, feedforward filtering and controller parameters on the change trend of AC impedance of flexible DC converter stations. 22 and 34 AC line operating conditions are considered respectively, and the AC system harmonic impedance scanning calculation is carried out for various operating conditions of Liuzhou Station and Longmen Station at the receiving ends. To avoid resonance, a 100 Hz low-pass filter should be added to the feedforward of the gantry station, with a control link delay of 300 μs, which will affect the dynamic response performance. The corresponding high-frequency harmonic resonance risk suppression method is proposed, which can provide a reference for suppression of the high-frequency harmonic resonance risk of the Kun-liu-long DC project.

Adaptive Back-stepping Stability Control Strategy for MMC Based on Legendre Polynomial

XU Lei, XIA Xiangyang, JING Huabing, LIU Yixuan, HE Yedan, YI Haigan

2022, 55(3): 18-27. DOI: 10.11930/j.issn.1004-9649.202101098

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In view of the poor stability control performance and frequent operation faults of the flexible HVDC transmission system due to the parameter changes of system dynamic model structure caused by serious signal interference or device temperature rise during the operation of the modular multilevel converter(MMC), an adaptive back-stepping stability control strategy is proposed based on Legendre polynomial. Firstly a dynamic model is established in a static a-b-c coordinate system, and the Legendre polynomial, which has advantages of simple structure and no modeling, is used to approximately compensate for the error value caused by the parameter changes in MMC, thus eliminating its effects on dynamic model. Then, the back-stepping control theory is used to select the state variables, construct the Lyapunov function, and obtain the control variables that meet the requirements of Lyapunov stability. Finally, simulation verification is carried out through PSCAD/EMTDC, which shows that the control strategy proposed in this paper has better control ability and robustness than the conventional PI control strategy.

Study of Vehicle-to-Grid Interaction Income Considering Scenario Coefficient

CHENG Hongbo, GUO Yuanxi, SHANG Zixuan, LI Yunxiao

2022, 55(3): 28-36. DOI: 10.11930/j.issn.1004-9649.202101099

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As the urgency degree of the grid demand for power varies due to the dynamic change of the grid, the income generated by vehicle-to-grid (V2G) interaction also differs under different urgency degrees. To achieve a more reasonable distribution of the interaction income, this paper proposed a distribution method of the V2G interaction income that considers the difference in the power grid scenario. The scenario coefficient is used to reflect the urgency degree of the grid demand for power, and equivalent substitution of ancillary services is discussed to analyze the V2G interaction income. The response probability of electric vehicle users under different electricity prices is taken into account and an improved bargaining game model is built to solve the electricity price for the optimal scenario response and thereby obtain the income distribution shares of the two sides participating in the V2G interaction. The effectiveness and superiority of the proposed income distribution model are verified through the comparative case analysis of the load reduction degree, income, and fair entropy of the distribution method among several response strategies.

Comparative Study on the Switchgear Partial Discharge Characteristics Based on Transient Earth Voltage and Pulse Current Detection Methods

XIE Rongbin, YANG Chao, SHEN Qiang, LI Shiyong, LUO Yong, YU Boning

2022, 55(3): 37-47. DOI: 10.11930/j.issn.1004-9649.202108103

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The transient earth voltage (TEV) method is studied in detection performance for switchgear partial discharge, and compared with the pulse current detection method. In addition, the detection capabilities of the two methods are studied for different types of partial discharge, and the similarities and differences of the PRPD (phase resolved partial discharge) spectra of four partial discharge types measured by two methods are analyzed. The variations of the detection results with the applied voltage are analyzed through calculating the statistical characteristics. The results show that, compared with the conventional high-frequency current transformer (HFCT) method, the TEV method has a lower signal-noise ratio in detecting switchgear partial discharge with a slightly inferior detection performance, but it is more suitable for detecting weak tip discharge; in terms of PRPD spectra, the two methods have strong consistency in pulse amplitude characteristics and phase intervals for different types of partial discharge, but there are some differences in pulse concentration and other aspects. With the change of applied voltage, TEV and HFCT methods have the same variation trend of skewness and steepness, and both methods can effectively reflect the discharge characteristics of partial discharge.

Effect of Moisture Content and Aging State on the Dielectric Properties of Silicone Oil

WANG Feifeng, GUO Jinming, TIAN Shujun, ZHUO Haoze

2022, 55(3): 48-56. DOI: 10.11930/j.issn.1004-9649.202109137

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The aging and dampness of silicone oil caused by long-term electrical and thermal combined stress and humid environment seriously threatens the safe and stable operation of the oil-filled cable terminals. Studying the influence of the moisture content and aging state of silicone oil on its dielectric properties is conducive to promoting the application of dielectric testing methods in the diagnosis of the insulation state of the silicone oil in oil-filled terminals. Therefore, unaged silicone is selected for testing on natural moisture absorption and electric-heat combined aging, and 6 groups of silicone oil samples with different moisture content and 6 groups of silicone oil samples with different aging states are prepared respectively. And then, the oil samples are tested on polarization and depolarization current (PDC). Based on the PDC testing results, the silicone oil with different insulation states are analyzed on DC conductivity and polarization loss factor spectra. Finally, the oil carrier migration and distribution model is used to calculate the relaxation parameter, which can sensitively characterize the concentration of moisture content in the silicone oil and the concentration of the by-products of silicone oil degradation. Thereafter, a quantitative relationship is established between this parameter and the insulation state of silicone oil.

The Control Method that Load Respond to Distributed Generation Fluctuation in Microgrid Based on Image Matching

CHEN Weidong, GUO Min, WU Ning, FENG Bin

2022, 55(3): 57-63,73. DOI: 10.11930/j.issn.1004-9649.202102029

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In order to improve the performance of intelligent regulation and control of microgrid, the load response distributed power fluctuation control method of microgrid based on image matching was proposed based on data-driven idea and artificial intelligence technology in view of the problem of load regulation strategy development of microgrid.Firstly, based on the multi-dimensional operation data of distributed power supply and adjustable load, a comprehensive source and load characteristic image of the microgrid in the next regulation period is constructed. Furthermore, the image similarity matching algorithm based on K-SURF for the comprehensive characteristics of source and charge of microgrid is proposed, so as to draw on the regulation strategy of microgrid with similar operating state in history to formulate the regulation strategy for the next cycle load response of distributed power generation. The simulation results of a typical microgrid example show that the proposed image similarity matching method can effectively search for the most similar historical operating state, and the load control strategy formulated by referring to the historical similar operating state control strategy can effectively track the fluctuation of renewable energy output. Improved the local consumption capacity of renewable energy in the microgrid.

Comparison of Synchronous Acquisition Trigger Methods in On-Line Monitoring Technology of Transformer Equipment

ZHU Yongcan, ZHANG Peng, TIAN Yi, HUANG Xinbo

2022, 55(3): 64-73. DOI: 10.11930/j.issn.1004-9649.202107135

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The dielectric loss angle and power factor angle are common characteristic parameters used in online monitoring technology of capacitive equipment, zinc oxide arresters and dry-type air-core reactors. Its measurement accuracy is mainly controlled by the time difference of synchronous acquisition. Firstly, the principle of on-line monitoring technology of HV electrical equipment based on phase measurement is analyzed, and the time difference requirement for synchronous acquisition trigger is checked. Then, based on the existing intelligent substation online monitoring systems, a study is made on the design schemes and implementation methods of four synchronous acquisition triggering technologies, namely satellite timing, short-range radio broadcast communication, station control layer IRIG-B code timing, and power supply voltage assisted measurement. The experimental results show that the satellite timing has the highest synchronous acquisition accuracy; the short-distance radio trigger mode is simple in structure and easy to expand; the IRIG-B code is good in stability but complex in wiring; the power voltage auxiliary measurement is susceptible to the frequency fluctuation of the power grid. These results can provide a technical support for the online monitoring design of intelligent substations.

An Energy Coordination Strategy for Island DC Microgrid With Photovoltaic and Storage System Based on Improved Consensus Algorithm

DING Yu, YU Aiqing, GAO Chun

2022, 55(3): 74-79. DOI: 10.11930/j.issn.1004-9649.202103061

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For bus voltage stability in DC microgrids, a voltage stability function for DC bus voltage is added to the multi-agent consensus algorithm.At the same time, taking the minimum operation cost of the controllable units as the objective function, combing with the conditions of power balance, a distributed energy management strategy for small photovoltaic DC microgrid is proposed to realize the optimal output of power. The distributed strategy has good convergence performance, which can effectively maintain the stability of DC microgrid. The simulation model of DC microgrid is built and the simulation results are analyzed to verify the effectiveness of the strategy.

GIS Shell Vibration Mechanism and Partial Discharge Optimization Diagnosis

ZHANG Li, QU Bin, WANG Yongning, CHEN Rong, LIU Baowen, ZHANG Shaojie, HAN Bin, MA Hongzhong

2022, 55(3): 80-86. DOI: 10.11930/j.issn.1004-9649.202108005

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In order to explore the mechanism of abnormal vibration of power equipment caused by electromagnetic induced vibration and partial discharge (PD) in GIS, the distribution model of induced eddy current and its electromagnetic force considering skin effect in GIS was established, and the development experiment of PD at metal tip of GIS was set up. The pulse current and the vibration signal of GIS shell are measured simultaneously when GIS PD occurs, and the vibration characteristics and mechanism of GIS PD are explored by integrating the electromechanical signal. It is found that there are obvious differences between electromagnetic induced vibration and PD induced vibration of GIS shell. The frequency of PD induced vibration of GIS shell is the same as that of pulse interval frequency, and the energy is concentrated at the frequency of 50Hz. Finally, the SVM model optimized by particle swarm optimization (PSO) is constructed to realize the pattern recognition of different discharge levels, and it is applied in practice.

Incentive Mechanism for Data Sharing of Power Material Procurement Based on Consortium Blockchain

SHI Qingsong, QIN Rui, XIAO Peng, OUYANG Liwei, XIONG Gang, ZHANG Hongxin, WANG Feiyue

2022, 55(3): 87-96. DOI: 10.11930/j.issn.1004-9649.202101087

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The traditional e-commerce platform of power industry is faced with the problems of high cost of e-payment, insufficient data integration in all links of supply chain, low security performance of network data, and lack of transaction transparency, which seriously restrict the further development of e-commerce platform of power industry. As blockchain technology has the characteristics of decentralization, openness, transparency and non-tamperability, this paper aims to apply blockchain technology to the e-commerce platform of the power industry, and constructs the core application system and key technologies of the e-commerce of the power industry based on consortium blackchain. In addition, an incentive mechanism based on integration is designed to promote data sharing of the procurement of electric power materials among power enterprises. The proposed scheme can optimize the transaction process and operation structure of the e-commerce platform in the power industry, promote the sharing of power material purchasing data among power enterprises, reduce the risk of information leakage and the redundancy of the transaction process, so as to better realize the interconnection of the e-commerce information value chain in the power industry.

A Novel Method for Voltage Sag Source Location Based on HHT and GA-BP

YANG Zhen, MA Yuchao, LI Li, LI Xin, MA Ziying

2022, 55(3): 97-104. DOI: 10.11930/j.issn.1004-9649.202007250

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Aiming at the low accuracy of traditional voltage sag source positioning methods, this paper proposes a new location method based on HHT and GA-BP. Firstly, the EEMD(ensemble empirical mode decomposition) Hilbert-Huang Transform (HHT) is used to process the voltage and current during the fault period, and the effective eigenvalues - the current real part Icosθ and system trajectory slope k are obtained. Then the GA-BP neural network is used to classify the effective eigenvalues to get the initial location of the voltage sag source. And then, the moth to flame optimization (MFO) algorithm is used to solve the mathematical model of voltage and current of the fault line, so that the precise location of the voltage sag source is obtained. At the same time, the fault types are distinguished according to the relationship between the three-phase voltage amplitudes. Finally, a simulation model of a dual power supply system is used to verify the proposed method, and the simulation results show that the proposed method has high accuracy and precision in positioning and can precisely locate the voltage sag source.

Multi Time Scale Reactive Power and Voltage Optimization of Distribution Network Considering Photovoltaic Multi State Regulation Capability

YANG Genye, SUN Rongfu, DING Ran, XU Haixiang, CHEN Can, WU Linlin, CHEN Qifang, XIA Mingchao

2022, 55(3): 105-114. DOI: 10.11930/j.issn.1004-9649.202012038

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As the penetration of Distributed Generators (DGs) grows larger, the fluctuation and uncertainty of DGs have posed great challenges to the power quality and stability of the distribution network. Considering that the existing slow-motion regulating equipment does not meet the requirements of reactive voltage regulation, a multi-time scale reactive voltage coordinated control scheme for distribution network is proposed. It is aimed to improve the voltage deviation and fluctuation caused by the random volatility of photovoltaic (PV) by considering the coordination regulation ability between the distributed photovoltaic multi-operation state and the traditional reactive power regulation equipment. The active power and reactive power of PV, capacitor operation and reactor operation are coordinated to achieve the goal both in day-ahead optimization and minutes’ optimization. Finally, the validity of the proposed method is verified by the simulations with a 21-node actual distribution system with distributed PVs in North Hebei grid.

Grading Assessment of Energy Index Considering Equipment Tolerance Characteristics

FAN Xingguan, XU Yonghai, NIU Chunhao, DENG Siying

2022, 55(3): 115-124. DOI: 10.11930/j.issn.1004-9649.202106022

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Considering the influence of user equipment's voltage tolerance characteristics on the assessment results, a system-side voltage sag grading assessment method is proposed to improve the energy index, which considers the equipment's tolerance characteristics. Firstly, an analysis is made of the comparison benchmark value of the energy index and the insufficient description of the difference in severity of the sag events in the uncertain area; And then, the comparison benchmark value and weight coefficient are constructed based on the voltage tolerance curve, and an improved energy index evaluation model is built to grade the severity of the sag event; Finally, the proposed method is used to analyze 24 voltage sag events occurring at a monitoring node, which have proved the rationality and effectiveness of the proposed method. The proposed method can be used for voltage sag assessment and governance of the actual power systems.

A New Method for Calculation of Transmission Line Tripping Probability Caused by Galloping of Iced Overhead Conductor

LIU Hui, MA Zengtai, LIN Jikeng, TIAN Hongqiang, YAN Bo, ZUO Chenliang

2022, 55(3): 125-132. DOI: 10.11930/j.issn.1004-9649.202009114

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The galloping of iced conductors seriously threatens the safety and stability of power systems, so it has become a focus for research to accurately calculate the transmission line tripping probability caused by the galloping of iced conductors. A new tripping probability calculation method is proposed based on the galloping equation, meterological information and fault information. Firstly, the probability distribution functions of wind speed and frozen rainfall are obtained using their respective historical samples; next, a single-degree-of-freedom galloping model of iced conductors is built according to the Newton law; and then, the Ritz-galerkin method is utilized to solve the galloping model to acquire the analytical expression of the galloping amplitude with the wind speed and icing thickness as independent variables; furthermore, the probability distribution function of icing thickness, which is the function of wind speed and frozen rainfall, is calculated using the probability distribution functions of wind speed and frozen rainfall, and then the probability distribution function of galloping amplitude is also calculated; finally, according to the Poisson distribution obtained by the historical fault records of galloping-caused tripping, the joint probability for the over-limit of galloping amplitude and the short-circuit fault is obtained, and the galloping-caused tripping probability of iced conductors is calculated using the Bayesian formula under the condition of over-limit of galloping amplitude. Case study has proved the effectiveness of the proposed method.

Calculation of Transmission Line Trip Probabilities under Forest Fire Condition

LIU Hui, YANG Tao, LIN Jikeng, WANG Jingjing, YAN Bo, LIU Xiao

2022, 55(3): 133-141. DOI: 10.11930/j.issn.1004-9649.202009003

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In recent years, line tripping incidents caused by forest fires occur frequently. How to accurately predict the line trip probability caused by forest fire has become one of the urgent issues that have attracted much attention. A new method for calculating transmission line trip probabilities is thus proposed in this paper using improved cellular automata forest fire spread model. Firstly some factors are introduced such as flame temperature, vegetation type, fire distance and precipitation, and the integrated impact of these factors on the line tripping is analyzed; then the improved cellular automata is used to predict the spread process of forest fires, and the accurate probability variation of line tripping caused by forest fire is thus obtained according to the spread situation. The effectiveness of the proposed method has been proved through case study, and it can provide a guide for the safe operation of power grid.

Resilience-Improving Based Optimization of Post-Disaster Emergency Maintenance Strategy for Transmission Networks

LIANG Haiping, SHI Haoyan, WANG Yan, LIU Yingpei, WANG Xinming

2022, 55(3): 142-151. DOI: 10.11930/j.issn.1004-9649.202009052

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Extreme natural disasters and other events are likely to cause large-scale failures of the transmission networks. In order to minimize the economic losses and improve the post-disaster resilience of transmission networks, firstly, according to the connotation of transmission network resilience, the expected system load recovery efficiency is proposed as the resilience evaluation index; secondly, the post-disaster emergency maintenance process of transmission networks is analyzed, and a collaborative optimization model of time-uncertainty based post-disaster emergency maintenance strategy is established for transmission networks, which not only considers the resilience-improving economy of transmission networks, but also the constraints such as resources and path planning in the process of post-disaster maintenance. An improved particle swarm optimization (PSO) algorithm is proposed for the optimization model, which uses such methods as the multi-dimensional indefinite length coding, sub-group collaborative optimization, and Monte-Carlo-simulation-based fitness evaluation to improve the standard PSO algorithm. The simulation results of an IEEE RTS-79 case show that the improved particle swarm optimization algorithm can effectively solve the proposed optimization model, and the results of the collaborative optimization model can effectively improve the transmission network resilience index and the economy of post-disaster emergency maintenance.

Coordinated and Optimized Operation of Waste Incineration Plant-Flue Gas Treatment-P2G with Carbon Cycle

HUANG Jingjie, LIU Louzhi, YIN Xufeng, LI Xueqin, PAN Xuan, ZHOU Renjun

2022, 55(3): 152-158. DOI: 10.11930/j.issn.1004-9649.202011007

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Aiming at the environmental protection problem that the CO₂ generated by waste incineration power plants is difficult to deal with, a waste incineration power plant-flue gas treatment-P2G coordinated and optimized operation model based on carbon recycling is constructed in this paper. The electricity-to-gas technology recovers CO₂ and synthesizes methane to realize carbon recycling and reuse. The model aims to maximize the comprehensive net income composed of electricity sales revenue, carbon emission costs, auxiliary fuel purchase costs, flue gas treatment and power-to-gas power operating costs. The operating periods of incineration power generation, flue gas treatment, flue gas collection, flue gas storage, and electricity-to-gas synthesis are the decision variables. The simulation results show that the model uses the real-time electricity price and the flue gas storage device to flexibly coordinate the power generation, flue gas treatment and power to gas operation state of the waste incineration power plant in different periods, which can effectively reduce the cost of auxiliary fuel purchase and carbon emission, increase the income of electricity sales, fully realize the carbon recycling, and have significant economic and social benefits.

Research on the Uniformity of Flow Field in the Low-Temperature Waste Heat Recovery Tower of Waste Heat Boiler Flue Gas

PAN Xiaowei, PENG Shuo, LI Shuo, ZHOU Xian, WANG Changjun, LIU Jun, WANG Ruiyuan

2022, 55(3): 159-166. DOI: 10.11930/j.issn.1004-9649.202102090

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The packed waste heat absorption tower can recover the sensible heat of the flue gas and latent heat of vaporization through the gas-water heat exchange process in the tower. Then the exhaust temperature is reduced, and a large amount of condensed water is recovered. The uniformity of the aerodynamic field in the tower greatly affects the cooling performance of the waste heat recovery tower. This article focuses on the counterflow waste heat recovery tower of a power plant. The influence of the inlet baffle and air distribution plate on the uniformity of the aerodynamic field in the tower is carried out. The results show that, adding the air distribution plate, multiple smaller air flows are formed at the exit of the V-shaped plate of the air distribution plate, which plays a role of rectification and uniform distribution. The uniformity of the flow field in the waste heat recovery tower has been further improved if increasing the inlet deflector on the basis of the air distribution plate. The waste heat recovery Tower flow loss will be increased when adding the air distribution plate. The flow loss of the waste heat recovery tower will be appropriately reduced when increasing the inlet baffle on the basis of the air distribution plate.

Regional Differences and Spatial Econometric Analysis of Wind Power Generation Performance in China

LI Cunbin, DONG Jia

2022, 55(3): 167-176. DOI: 10.11930/j.issn.1004-9649.202105178

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In recent years, wind curtailment in China has seriously affected the utilization rate of wind power resources and hindered the process of China’s energy structure transformation. To effectively improve wind power performance and speed up the progress of energy revolution, this paper conducts differentiated research on regional wind power development of various provinces in China. The DEA-TOPSIS model is used to measure wind power performance, and the result is compared with that of the super efficiency DEA model. It is verified that the proposed model is more suitable for wind power performance evaluation. The space panel model is introduced to analyze the influencing factors in wind power performance, and the differentiation strategy is formulated to promote the development of wind power. The results show that the pure technical efficiency of wind power in various provinces is lower than the scale efficiency as a whole, and the geographical proximity has a positive impact on China’s wind power development. At present, the main factors affecting the performance of wind power in China are the level of regional economic development and wind curtailment. The research provides a decision-making reference for the optimization of wind power operation and management in various provinces.

Additional Damping Cooperative Control Method of Virtual Synchronous Wind Farm and Photovoltaic Power Stations

SHENG Shixian, ZHOU Xin, WANG Delin, LIAO Jiasi, LI Jingqi, KANG Jitao

2022, 55(3): 177-186. DOI: 10.11930/j.issn.1004-9649.202011043

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The rapidly growing grid-connected capacity of new energy units may cause low-frequency oscillations in the power system, and thus new energy units based on wind power and photovoltaic (PV) should have the ability to restrain low-frequency oscillations. This paper takes the system including wind farm and PV power stations as the research object and clarifies the principle of virtual synchronous generator (VSG) control and additional damping control for doubly-fed induction generator (DFIG) to increase system damping. With the change of active power at the grid-connection point of DFIG as input, additional damping controllers are designed on the active power control loop of the VSG wind farm and the controller of PV power stations respectively. Then, the cooperative control strategies are designed according to the operating areas of DFIG. When DFIG is operating in the constant speed zone, considering the slow response speed of the pitch control and the unsatisfactory effect of suppressing oscillations, DFIG no longer participates in the additional damping control, and the PV power station outputs additional power to compensate the shortcomings of DFIG. Finally, a simulation system including wind farm and PV power stations is established, and the effectiveness and correctness of the cooperative control method are verified through Prony analysis and time-domain simulation verification.

Experimental Study on Wind Acceleration Effect in Wind Farms with Complex Terrain

YAN Xiaosheng, LI Yue, GAO Xiaoxia, WANG Xi

2022, 55(3): 187-192,212. DOI: 10.11930/j.issn.1004-9649.202011049

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Sloping land makes the speed of the inflow on the flat land increase after a certain height difference, which results in the wind acceleration effect. Experiments were conducted in a mountain wind farm to obtain the flow field data of the slope wind field and study the influence of slope terrain on the wind acceleration effect. Experimental results show that the acceleration effect is related to the altitude of the slope, and the measured acceleration ratio at high altitudes is only about 16.9% of that predicted by Taylor’s original algorithm. Moreover, both the slope and the wind direction are also factors affecting the acceleration effect. Generally, the acceleration effect becomes more prominent when the slope is greater. In this experiment, the acceleration ratio in the positions with a larger slope is increased by 61.6%, and the acceleration ratio on the crosswind side of the slope is about 10% larger than that on the windward side. Meanwhile, the reasons for errors generated by Taylor’s original algorithm are analyzed, and the modified formula of Taylor’s method suitable for complex terrain is proposed in this paper.

Two-level Optimal Configuration of User-side Integrated Energy System Considering Interval Uncertainties

LU Bingwen, WEI Zhenbo, WEI Pingan, GUO Yi, HU Rong

2022, 55(3): 193-202. DOI: 10.11930/j.issn.1004-9649.202009108

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In order to solve the problem of the lack of consideration of uncertain factors in the planning and operation of the user-side integrated energy system, this paper proposes a two-tier optimal configuration model. For this reason, the uncertainty of load, renewable energy power generation and energy prices is expressed in the form of interval numbers, with the annual investment cost and annual operating cost of the equipment as the target, and considering the impact of the fluctuation level of the operating cost, a consideration interval uncertainty is constructed. The two-level optimal configuration model of the user-side integrated energy system on the user side, the upper layer uses particle swarm optimization, the lower layer obtains the interval solution of the system operation through the interval linear programming method, and the optimal solution of the model is obtained through mutual iteration. Finally, a simulation example is carried out. The results show that the configuration of energy storage equipment in the user-side integrated energy system can reduce system cost fluctuations, and the impact of load uncertainty, energy price uncertainty and weight coefficients $ \lambda $ on energy equipment configuration capacity and system operating costs are compared and analyzed. The model can provide planning schemes for operators and has engineering practical significance.

Energy Efficiency Evaluation Model of Park Customers Based on PSR and Improved Grey TOPSIS

ZHAO Hongshan, LI Jingxuan

2022, 55(3): 203-212. DOI: 10.11930/j.issn.1004-9649.202010084

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In order to improve the energy efficiency level of park customers, it is necessary to evaluate the energy efficiency level of customers to find out the weak links of energy consumption before energy efficiency optimization. Considering the logical dynamic relationship between energy efficiency indicators, the dynamic energy efficiency index system is constructed by selecting evaluation indexes from three dimensions based on PSR model. Combining principal component analysis and correlation analysis, the index system is optimized and redundant indexes are eliminated. An improved Grey TOPSIS energy efficiency evaluation model is constructed where entropy weight method is introduced to calculate the objective weight of indexes. The weighted grey correlation degree is used to replace the Euclidean distance as the distance measurement to evaluate the customers energy efficiency level, and the energy consumption status is analyzed from three dimensions. Finally, the energy efficiency level of 10 typical park customers is evaluated. The result shows that the comprehensive energy efficiency evaluation results of customers with good response performance are higher, which verifies the feasibility of PSR index system. Compared with the results of other methods, the effectiveness of the evaluation model is verified.

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