Table of Content

28 January 2023, Volume 56 Issue 1

Previous Issue    Next Issue

Special Contribution

Day-Ahead Optimal Dispatching of Wind-Solar-Thermal Power Storage System Considering Deep Peak Shaving of Thermal Power

LI Xiongwei, WANG Xin, GU Jiawei, XU Jiahao

2023, 56(1):  1-7,48.  DOI: 10.11930/j.issn.1004-9649.202206084

Asbtract ( )   PDF (8222KB) ( )  

References | Related Articles | Metrics

Realizing the complementary operation of wind, solar, and thermal power storage by deeply mining the deep peak-shaving capacity of thermal power units is an important means to deal with the large-scale grid-connected consumption of new energy. This paper proposes the calculation methods of the deep peak shaving and climbing cost of thermal power units, pollutant penalty cost, operation cost of the energy storage system, and penalty cost of new energy power abandonment. In addition, it builds the day-ahead optimal dispatching model of the wind-solar-thermal power storage system considering deep peak shaving of thermal power. Taking the maximum wind and solar output, the minimum net load fluctuation, and the lowest system operation cost as the optimization objectives separately, this study simulates and calculates the optimal dispatching strategies of the wind-solar-thermal power storage system with a high proportion of new energy on a typical day under different peak-shaving depths of thermal power units. The results show that the built model can realize the calculation of the optimal dispatching strategies of wind, solar, and thermal power storage under different optimization objectives. A larger deep peak-shaving capacity of thermal power units can effectively reduce the power abandonment rate of new energy.

Electricity Price Marketization Reform and Price Supervision

Prediction of Power System Cost and Price Level Under the Goal of “Carbon Peak and Carbon Neutralization”

SUN Qixing, ZHANG Chao, LI Chengren, YOU Peipei, GAO Xiao, ZHAO Qian, XU Zhao, LIU Sijia, LI Yanlin

2023, 56(1):  9-16.  DOI: 10.11930/j.issn.1004-9649.202208069

Asbtract ( )   PDF (5117KB) ( )  

References | Related Articles | Metrics

In the process of achieving the goal of carbon peak and carbon neutralization in the power system, the power supply structure and grid form will change significantly, and the system cost will also change accordingly. On the basis of comprehensive consideration of the changes in power supply structure, power generation cost, fuel cost, grid investment and other factors, this paper adopts the business period method and the “cost + income” model to forecast the cost and price level of power system in the mid to long-term. The research results show that the cost of each link of the power system will increase in the future, among which the cost of the power supply side will increase rapidly before 2040 and tends to be relatively stable afterwards, while the cost of the power grid side will increase slightly. This study can provide a reference for further improving the electricity price mechanism and marketization system, as well as strengthening the power system cost facilitation and fair sharing.

Time-Sharing Trading Price Formation Mechanism and Model of China’s Mid to Long-Term Electricity Market

HUANG Shanshan, YE Ze, LUO Mai, CHEN Lei, WEI Wen, YAO Jun

2023, 56(1):  17-27.  DOI: 10.11930/j.issn.1004-9649.202208082

Asbtract ( )   PDF (5252KB) ( )  

References | Related Articles | Metrics

The time-sharing trading of mid to long-term electricity market is one of the important reform measures for China's electricity market. Aiming at the unreasonable and imperfect problem of current time-sharing trading price formation mechanism, a novel time-sharing trading price formation mechanism and model is proposed for China’s mid to long-term electricity market. Firstly, the paper analyzes the factors that influence China’s mid to long-term time-sharing trading prices, and puts forward four typical scenarios of mid to long-term power transaction. Then, considering the production cost and users’ utility, the paper proposes four cost pricing mechanisms suitable for mid to long-term market time sharing trading, including system average cost pricing, user value of lost load pricing, system marginal cost pricing and power generation company value of lost load pricing, and a time-sharing trading pricing model is proposed based on cost pricing mechanism. Finally, the validity of the model is verified through a case study of the actual data of H province.

User Side Distributed Energy Storage Trading Strategy Based on Dynamic Electricity Price Mechanism

GUO Zhidong, HU Cungang, RUI Tao, LUO Kui, LIN Zhenfeng

2023, 56(1):  28-37.  DOI: 10.11930/j.issn.1004-9649.202206019

Asbtract ( )   PDF (5100KB) ( )  

References | Related Articles | Metrics

User-side distributed energy storage has the ability to optimize user power load curve and coordinate renewable energy generation at the consumption system side. In this paper, a user-side distributed energy storage trading strategy is proposed based on dynamic electricity price mechanism. Firstly, a day-ahead power dispatching model is constructed for the user-side distributed energy storage and distribution system with full consideration of the uncertainty of new energy output and user’s power demand. Secondly, according to the impact of dynamic electricity price mechanism on the user-side distributed energy storage scheduling plan and the system-side renewable energy consumption level, a power trading model is established for distribution network operators (DNOs) and user-side distributed energy storage owners (DEOs) based on master-slave game, and the metaheuristic algorithm is used to obtain the equilibrium solution of the game model. Finally, it is verified through a case study that the proposed power trading strategy can effectively improve the DNO’s economic benefits and renewable energy accommodation level and reduce the user-side operating costs.

Business Models of Electric Vehicle Aggregators Considering Electricity Price Uncertainty and Capacity Decay

LI Xudong, YANG Ye, LI Fanqi, SHI Quanyou, TAN Zhongfu

2023, 56(1):  38-48.  DOI: 10.11930/j.issn.1004-9649.202210063

Asbtract ( )   PDF (5227KB) ( )  

References | Related Articles | Metrics

As a mobile energy storage facility, electric vehicles can enhance the stability of power system through vehicle network coordination. With the rapid development of electric vehicles, how to design the business model of electric vehicle charging and discharging has become an urgent problem that needs to be solved. In view of this, this paper designed two business models for EV aggregators, including their sole participation in spot market and joint participation in spot market and auxiliary service market. At the same time, considering the influence of electricity price uncertainty and battery capacity decay, economic calculation and multi-factor sensitivity analysis were carried out for the above-mentioned two models. Case study shows that the EV aggregators′ joint participation in spot market and auxiliary service market is economically better than their sole participation in spot market. Finally, based on the research results, the paper designed a business scheme for electric vehicle aggregators participating in the electricity market.

Incentive Compatible Interactive Compensation Electricity Price Contract Model for Segmented Users

YU Qingyun, SHU Yunhao, DAI Xiaomei

2023, 56(1):  49-55.  DOI: 10.11930/j.issn.1004-9649.202204071

Asbtract ( )   PDF (4770KB) ( )  

References | Related Articles | Metrics

The friendly interaction between electricity users and power grid companies is an effective way to solve the current contradiction between energy supply and demand. In order to encourage electricity users to participate in power interactions, it is necessary to design a reasonable interaction mechanism. An incentive compatible interactive compensation price contract model is thus proposed for different types of users. Based on nonlinear pricing theory, the model takes the maximization of the interests of power grid companies as the decision-making goal, and considers the incentive compatible constraints of electricity users to determine the optimal interaction volume and compensation price corresponding to different types of users. Case study shows that the proposed pricing model has both pricing efficiency and operability. It can not only ensure the maximization of the interests of power grid companies, but also well encourage users to participate in power interactions. At the same time, it can guide users to disclose real type information, thus meeting the incentive compatibility characteristics of the users. It has both practical social and economic significance in the context of power market.

Comparison of PoLR Service Mechanism of Electricity Market in Typical Countries and Implications for China

CAO Fang, LUO Jinben

2023, 56(1):  56-67.  DOI: 10.11930/j.issn.1004-9649.202208074

Asbtract ( )   PDF (4531KB) ( )  

References | Related Articles | Metrics

The provider of last resort (PoLR) service mechanism is an important part of the stable operation of the electricity retail market. With the comprehensive liberalization of China’s electricity retail market, it is urgent to deeply study the design connotation of the PoLR service mechanism in typical national electricity markets, and to design a PoLR service mechanism that adapts to the development of China’s electricity retail market. Firstly, this paper analyzed and compared the design of PoLR service mechanism in three typical electricity markets: the United Kingdom, Australia and Texas of the US, including the start of PoLR service, the selection of PoLR provider, the price mechanism, the cost recovery mechanism and the service period, etc. Then, it investigated the practice of China’s PoLR service mechanism, and analyzed the characteristics of China’s PoLR service mechanism based on other country’s experiences. Finally, based on the experience of typical countries and the reform environment of China's electricity retail market, relevant suggestions are put forward for the design of China's PoLR service mechanism.

International Practice of Generation Capacity Adequacy Guarantee Mechanism and Its Implications for China’s Electricity Market

HUANG Haitao, XU Jiadan, GUO Zhigang, JIN Jianbo

2023, 56(1):  68-76.  DOI: 10.11930/j.issn.1004-9649.202205004

Asbtract ( )   PDF (4644KB) ( )  

References | Related Articles | Metrics

The green transformation of electrical energy and acceleration of spot market make it increasingly urgent to establish a guarantee mechanism of generation capacity adequacy and its path selection in China. Therefore, this paper reviewed the international practices of capacity adequacy guarantee mechanism, comprehensively compared three mechanisms of scarcity pricing, capacity market and capacity subsidy electrovalence in terms of basic principles, overall framework and core systems, advantages and disadvantages of mechanisms and applicable conditions. Focusing on the capacity market, the paper also compared three types of market models including decentralized model, centralized model and reliable options model, proposed a basic framework system with the capacity quota, qualification examination and market transaction as the core system, and studied the auction system design and capacity demand curve calculation method for various markets. In addition, the paper introduced the principle and methods for checking the capacity electricity price and adequacy capacity in Chile, and discussed the limitations of scarcity pricing mechanism in social and political aspects and the dilemma of supervision. Finally, some suggestions are put forward for staged construction of capacity adequacy guarantee mechanism in China, which are suitable for the construction and development of China's electricity market.

UK Frequency Response Service Markets and Their Implications for China’s Frequency Regulation Market Construction

YE Wensheng, JING Zhaoxia, XUAN Zongheng

2023, 56(1):  77-86.  DOI: 10.11930/j.issn.1004-9649.202206029

Asbtract ( )   PDF (4414KB) ( )  

References | Related Articles | Metrics

The high proportion of renewable energy increases the demand for high-performance frequency response services, which brings challenges to the construction of electricity markets. Ancillary service market mechanism is the key to obtain frequency response services economically and reliably. China is in a critical period of electricity market building. It is therefore necessary to learn from the experiences of foreign advanced markets. This paper introduces the UK frequency response service markets in detail, including the performance requirements, trading mechanism and response mechanism of traditional frequency response services products such as mandatory response services and firm frequency response, and new frequency response services products such as dynamic low high, dynamic containment and so on. An analysis is made on their decentralized, multi-market, long period and high transparency characteristics. Finally, some suggestions are put forward on the development of Chinese frequency response markets .

Power System

A Method to Evaluate the Contribution of Electrochemical Energy Storage Participating in Frequency Regulation Market

SONG Shaoqun, XIONG Jiali, ZHANG Weijun, HUI Dong, NIU Meng, DAI Liyu, CAI Qiang

2023, 56(1):  87-95.  DOI: 10.11930/j.issn.1004-9649.202210062

Asbtract ( )   PDF (3445KB) ( )  

References | Related Articles | Metrics

Electrochemical energy storage responds to tie-line power deviation in seconds, while the indexes CPS1 and CPS2 that measure the tie-line power deviation are computed by the cumulative value of tie-line power deviation in minutes, thus making it hard to objectively evaluate the contribution of energy storage to frequency regulation. To this end, a method is proposed to evaluate the contribution of electrochemical energy storage participating in the frequency regulation auxiliary service market. In this method, the “area control error” is used as an influencing variable to indicate the frequency regulation effect of energy storage power stations, and a correlation is established between “frequency regulation power of energy storage power station” and “area control error” to obtain the effect value of energy storage frequency regulation on area control error, eventually constructing an index to measure the frequency regulation contribution of energy storage. Based on the confidence level, the distribution of frequency regulation contribution index of energy storage is analyze to determine the contribution and economic benefits of energy storage in the frequency regulation market. The proposed method is verified through the actual operation data of a provincial power grid, which shows that the proposed method can accurately measure the frequency regulation contribution of energy storage, providing a reference for reasonably formulating the mechanism of energy storage participating in frequency regulation auxiliary service.

Optimization Design of Indoor Substation Ventilation and Noise Reduction Based on Deep Reinforcement Learning

TANG Jinhui, WU Fayuan, ZHI Yanli, MAO Mengting, DAI Xiaomin

2023, 56(1):  96-105,118.  DOI: 10.11930/j.issn.1004-9649.202211051

Asbtract ( )   PDF (6482KB) ( )  

References | Related Articles | Metrics

In view of the equipment safety problems caused by the high operation temperature of the indoor substations and the disturbing noise problems caused by relevant heat dissipation measures, this paper proposes a method for optimizing the design parameters of indoor substation air inlets based on finite element simulation and deep reinforcement learning to obtain the optimal ventilation and heat dissipation effects. Firstly, the temperature field, fluid field and sound field of the indoor substations are modeled and simulated with the finite element analysis method. Then, based on a large number of simulation data, the convolutional neural network is used to establish the prediction model of temperature and noise. Finally, considering the noise constraint, the maximum entropy reinforcement learning framework based SAC algorithm is used to optimize the design parameters of the air inlets with the goal of minimizing the indoor temperature of the substation. The research results show that the optimized air inlet design scheme can effectively reduce the indoor temperature in the substation, and at the same time make the noise meet the requirements of national regulations.

Reactive Power Compensation Capacity Optimization Method Based on BSSSO Algorithm

QI Shenglong, LI Lei, HE Yupeng, ZHU Lin, WANG Fang, ZOU Hongbo

2023, 56(1):  106-111.  DOI: 10.11930/j.issn.1004-9649.202106025

Asbtract ( )   PDF (3357KB) ( )  

References | Related Articles | Metrics

The objective of reactive compensation capacity is to minimize the active power loss and take into account the voltage balance. Firstly, according to the actual optimization of reactive power compensation capacity, a multi-objective reactive power compensation capacity optimization model considering active power loss, voltage deviation and voltage stability was established. Then, a BSSSO algorithm based on bird swarm algorithm (BSA) and shuffled shepherd optimization algorithm (SSOA) is proposed to optimize reactive power compensation capacity. Finally, the proposed method is verified by a simulation example, and the results show that the proposed method has superior performance and can take into account the balance of all indexes.

A Dynamic Reactive Power Optimization Algorithm for Regional Power Grid Based on Decoupling Interior Point Method and Mixed Integer Programming Method

ZHANG Jie, ZHENG Yunyao, LIU Shengchun, MA Yongfei, YAN Wei, WANG Hengfeng

2023, 56(1):  112-118.  DOI: 10.11930/j.issn.1004-9649.202106051

Asbtract ( )   PDF (3568KB) ( )  

References | Related Articles | Metrics

Dynamic reactive power optimization plays an important role in improving the voltage quality of power grid, decreasing the network loss and reducing the daily action times of discrete voltage regulators. Mathematically, it is a multi-period large-scale nonlinear mixed integer programming problem with absolute value constraints, and its efficient solution is a difficult problem. Therefore, this paper proposes a two-stage dynamic reactive power optimization algorithm based on decoupling interior point method and mixed integer programming. Firstly, the sigmoid function is used to deal with the absolute value constraint to realize the continuity of the original model, and the idea of decoupling interior point method is used to construct the diagonal band edge structure of the KKT modified equation, so as to realize the time block decoupling and efficient solution of the model. Secondly, the original model is linearized near the current continuous solution, and a mixed integer linear programming model involving all constraints of the original model is constructed, so as to determine the optimal solution of the discrete reactive power control equipment. The effectiveness of the proposed algorithm is verified through simulation of a 26 bus example.

Distribution Network Reconfiguration Considering Distributed Generation and Electric Vehicle Cluster Scheduling

XIE Xueyuan, LIU Xiaoxiao, LI Chao, HU Zipeng, LIU Kai, CHEN Tao

2023, 56(1):  119-125.  DOI: 10.11930/j.issn.1004-9649.202109121

Asbtract ( )   PDF (3467KB) ( )  

References | Related Articles | Metrics

Along with the connection of numerous flexible resources such as distributed generation and electric vehicles (EVs) to distribution networks, higher requirements are raised on system security and reliability. A distribution network reconfiguration method based on distributed generation and EV cluster scheduling is thus proposed to improve the system security and reliability. With consideration of voltage deviation, the network topology structure is reconstructed by taking the failure loss cost of power grid as an economic index to measure the power network reliability. Firstly, a distribution network reconfiguration model is established to minimize the comprehensive cost by taking the switching state of power lines, the charging and discharging state and power of EVs as decision variables. Then, the symbiotic search algorithm is used to solve the reconfiguration model. Finally, the effectiveness of the proposed method is verified via simulation of a distribution system.

A Voltage Balancing Control Strategy for Modular Multilevel Converter Based on Allowable Capacitance Voltage of Sub-modules

ZHANG Binqiao, LI Cheng, LI Zhenxing, XIAO Bowen, LIU Chuang, WANG Fei

2023, 56(1):  126-131.  DOI: 10.11930/j.issn.1004-9649.202107126

Asbtract ( )   PDF (4317KB) ( )  

References | Related Articles | Metrics

Aiming at the problems of high switching frequency, large switching loss and large amount of computation in traditional voltage balancing strategy for modular multilevel converter (MMC), an improved capacitor voltage balancing control strategy is proposed. The sub-module (SM) voltage is constantly kept in the specified range through introducing the allowable value variable of capacitor voltage, consequently reducing the loss of power devices. In the meantime, all the sub-modules need not to be sorted in each control cycle, thus further reducing the amount of computation of the control strategy. Finally, the Matlab/Simulink-based simulation is carried out and the results show that the proposed strategy can significantly reduce the switching times of power devices per unit time.

Prediction of Dissolved Gas Concentration in Transformer Oil Based on Hybrid Mode Decomposition and LSTM-CNN

CHEN Tie, ZHANG Zhifan, LI Xianshan, CHEN Yifu, LI Hongxin

2023, 56(1):  132-141.  DOI: 10.11930/j.issn.1004-9649.202210089

Asbtract ( )   PDF (4290KB) ( )  

References | Related Articles | Metrics

Predicting the concentration of dissolved gas in oil can help to know in advance the operation trend of transformers. A prediction method is thus proposed based on hybrid mode decomposition and LSTM-CNN network to achieve accurate gas concentration prediction. Firstly, in order to eliminate the influence of mode aliasing and residual white noise in the decomposition, the gas sequence is decomposed with ICEEMDAN to weaken the non-stationarity of the sequence. Then, the VMD is used to decompose the high frequency components after aggregation reconstruction to reduce the complexity of the high frequency components. Finally, in order to enhance the fitting of the model to the temporal and spatial features of the sequence, the TA-LSTM-CNN is used to predict the decomposition components and reconstruct the gas concentration data. Case study shows that the proposed model has stronger prediction performance than other models, which can provide strong support for subsequent fault prediction.

A Particle Swarm Optimization Algorithm for Smart Grid Voltage Collapse Path

XU Jie, WANG Shinong

2023, 56(1):  142-149.  DOI: 10.11930/j.issn.1004-9649.202102037

Asbtract ( )   PDF (3292KB) ( )  

References | Related Articles | Metrics

With the deep research of smart grid system, an equivalent model of smart grid system is studied for the voltage collapse path of complex smart grid system, and the brittleness relationship of the system is analyzed with AGENT diagram. An particle swarm optimization algorithm for optimizing the collapse paths when brittleness occurs is used to give the influence of the brittleness inside the system on the system’s stability and the solutions to the multiple collapse transmitting paths when brittleness is excited, and the collapse paths are analyzed. Based on the model of a 35kV smart grid primary system, the overall system performance is effectively optimized through prediction and control of the brittleness voltage collapse path of smart grid, which is of great significance to the design and control of the smart grid systems. The results show that the collapse of smart grid system nodes is transmitted between subsystem layers, which leads to the voltage collapse of the whole system.

ECC Based Load Information Protection Scheme for Electric Vehicle Users

YAN Renwu, ZHENG Yang, LIN Zhixiong, LIN Yihan, YU Zhipeng, ZHANG Wenfeng

2023, 56(1):  150-157.  DOI: 10.11930/j.issn.1004-9649.202206042

Asbtract ( )   PDF (4284KB) ( )  

References | Related Articles | Metrics

In the trend of smart grid, data transmission and exchange between power companies and users become more frequent and efficient. The communication network is often attacked or eavesdropped. In order to ensure that the user 's electricity data is not maliciously tampered during transmission, an information protection scheme for electric vehicle users is proposed. By improving the addition operation and scalar multiplication operation, the traditional elliptic curve cryptography（ECC） is lightly optimized to overcome the problem of limited smart meter resources in the two-way interactive environment of the power grid. On this basis, the load decomposition algorithm is designed as a test tool for the encryption scheme to decompose the encrypted power data. Finally, the reliability and security of the proposed scheme are verified by a simulation example.

New Energy

Reliability Evaluation of Photovoltaic System Based on Time Varying Factors

ZHU Lin, HAN Tao, DONG Yinghua, YU Yabo, XUE Yulong

2023, 56(1):  158-165.  DOI: 10.11930/j.issn.1004-9649.202102030

Asbtract ( )   PDF (6323KB) ( )  

References | Related Articles | Metrics

With the large-scale development of photovoltaic (PV) generations, the reliability level of PV stations has attracted more and more attention. A reliability evaluation method of photovoltaic generation is proposed based on time-varying factors. By analyzing the operation mechanism of PV generation system, the component failure mode and its impact on output power, a probabilistic model of system output power is proposed and the reliability evaluation indices of PV system are established, and a six-state space model of PV system is constructed as well. Based on the sequential Monte Carlo method, the operational reliability of a 50 MW PV station is evaluated with consideration the climate conditions, component aging and radiations. The simulation results show that the proposed model and indices can effectively reflect the actual operation state, output level and fault conditions of the system, which can provide support for the operation and maintenance of PV stations.

Technology and Economics

Prediction Method and Prospect of Unit Consumption of Main High Energy Consuming Products Based on Technical Analysis

LIU Qing, ZHANG Chenglong, XIONG Huawen, WENG Yuyan, ZHANG Hua, WANG Hong, TAN Qingkun, YAO Li

2023, 56(1):  166-172.  DOI: 10.11930/j.issn.1004-9649.202102003

Asbtract ( )   PDF (2624KB) ( )  

References | Related Articles | Metrics

High energy consuming industry is an important terminal energy consumption sector. Studying the change trend of unit consumption of main products in this industry is of great significance to grasp the trend of China's energy consumption. Considering the impact of energy-saving technology promotion and production capacity upgrading, a product unit consumption model based on technical analysis is established to predict the unit consumption of main products in high energy consuming industries during the 14th Five-Year Plan period. The results show that in 2025, the unit consumption of cement, steel, electrolytic aluminum, alumina, refined copper, synthetic ammonia, caustic soda and calcium carbide in the main products of high energy consuming industries will be 49, 239, 1609, 99, 36, 565, 327 and 385 kg standard coal / ton respectively, down 7.0%, 6.6%, 2.1%, 31.5%, 16.3%, 6.0%, 5.0% and 2.3% respectively compared with 2020, among which electrolytic aluminum has the highest unit consumption while alumina has the largest decline.