Table of Content

30 November 2021, Volume 0 Issue 11

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Overview

Review of Power System with High Proportion of Renewable Energy

WENG Zhimin, ZHU Zhenshan, WEN Buying, ZHENG Hailin, CHEN Zhesheng, LIN Wenjian

2021, 0(11):  1-7.  doi:10.16628/j.cnki.2095-8188.2021.11.001

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With the proposal of double carbon goal,new energy power generation has developed rapidly.In the future,a high proportion of renewable energy will be integrated to the power grid,which will have a significant impact on the power system.The impact of high-proportion renewable energy on power system modeling,operation and planning is analyzed.The research status of high proportion renewable energy systems in respect of mathematical model,planning scheme,demand response,energy storage and application of artificial intelligence is presented.The problems in the research of high proportion renewable energy systems are pointed out.Finally,the future development directions of renewable energy systems are summarized,including system construction,power system flexibility,renewable energy integration technology and application of artificial intelligence.

Research & Analysis

Technology Analysis on Energy Storage Power Station Under Double Carbon Target

LI Jianlin, QU Shukang, ZHOU Yi, MA Suliang

2021, 0(11):  8-14.  doi:10.16628/j.cnki.2095-8188.2021.11.002

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In order to promote the realization of the national “dual-carbon” goal and help the energy transition, the energy storage power stations are important technical means to promote the consumption of new energy and ensure the safe and stable operation of the power grid.The two ministries and local government departments have successively issued a number of policies to promote my country’s new energy construction of energy storage power station.From the perspective of my country’s successive releases of relevant policies,the structure and working mode of energy storage power stations are analyzed.From the perspective of the life cycle,the cost input,the benefits and the main parameters of the partly cost estimation are considered during the construction of the energy storage power station.Finally,combining my country’s existing energy structure, the relevant suggestions are given.With the hopes that energy storage power stations play multiple roles such as new energy consumption,the basis and decision-making guidance for the construction and operation of energy storage power stations can be provided.

Optimal Dispatching Method of Wind-Hydrogen Hybrid System Considering Heat Balance of Hydrogen Energy Storage

SI Yang, CHEN Laijun, MA Linrui, GAO Mengyu, CHEN Xiaotao, MEI Shengwei

2021, 0(11):  15-21.  doi:10.16628/j.cnki.2095-8188.2021.11.003

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When wind-hydrogen hybrid system (W-HHS) participates in grid,the heat demand characteristics of hydrogen energy storage system (HESS) working intermittently become the key factor affecting system dispatching.A HESS model with waste heat utilization system is established.Under the heat balance constraints composed of heat power balance and thermal energy balance of HESS,an optimal dispatching method of W-HHS is proposed to improve the profit and meet the constraints of tracking grid dispatching curve.Finally,the proposed model and method are verified and analyzed through an example of Qinghai wind plant data.The results show that the heat balance constraints of the HESS have an important impact on the operation and dispatching of the W-HHS.The proposed dispatching method improves the operation reliability of the W-HHS on the premise of ensuring the heat power balance and thermal energy balance of the HESS.Parameter analysis shows that reducing the heat dissipation coefficient can decrease the impact of heat balance constraints on the dispatching strategy of W-HHS and improve the grid connected power of wind plant.

Capacity Configuration and Optimal Operation Method of Energy Storage Participating in Grid Auxiliary Peak Shaving Based on Minimum Operating Cost

LI Yuxing, LU Yu, LI Hao, WANG Dong, MA Ning, HAN Xiaojuan

2021, 0(11):  22-29.  doi:10.16628/j.cnki.2095-8188.2021.11.004

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From the point of view of peak shaving compensation and coal saving,a capacity configuration and coordinated control method of energy storage participating in power grid auxiliary peak shaving based on the minimum operating cost is proposed.Aiming at maximizing the net profit of the system,the optimal capacity configuration model of energy storage participating in auxiliary peak shaving is established.ABC and PSO algorithms are respectively used to solve the model for the optimal capacity configuration of energy storage systems.With the minimum operating cost of the system as the objective function,an optimized control model for energy storage to participate in the auxiliary peak shaving of the grid is established.After coordination and optimization,the system wind abandonment rate is reduced to 1.078 8%,and the total system operation cost has been reduced to 1 401.08 million yuan.The validity and correctness of the method are verified by simulation analysis of the actual operation data of a power grid in a province.

Research on Safe Transaction Mechanism of Blockchain Energy Storage System Based on Automatic Price Adjustment Formula

LÜ Lixing, LIU Hua, XU Lei, YU Yong, ZHANG Jianbo

2021, 0(11):  30-35.  doi:10.16628/j.cnki.2095-8188.2021.11.005

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In the current electricity market pricing system,the degree of centralization centered on the grid is too high.With the development and progress of science and technology,blockchain technology has been introduced into power transactions,which has become a reasonable solution to the excessively high degree of centralization of power transactions.In order to solve the security and privacy issues in the transaction process,a secure transaction mechanism of the blockchain power transaction system based on the automatic price adjustment formula using asymmetric encryption technology is designed,and the corresponding price adjustment mechanism is designed for this mechanism.Finally,the data is used to verify the feasibility of price adjustment and price backtracking in the electricity trade.

Contribution Evaluation and Sensitivity Analysis for New Energy Accomodation Key Factors

ZHANG Bin, LIU Jie, QIU Gang, LIU Dagui, LI Guoqing, XIAO Guilian, HAO Hongyan

2021, 0(11):  36-41.  doi:10.16628/j.cnki.2095-8188.2021.11.006

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With the introduction of carbon neutrality and carbon peak goals,the large-scale development of wind energy and solar energy,and technological progress,new energy will gradually replace fossil energy power generation as the dominant energy source.With further development,the problem of new energy consumption still exists.Analysis of the factors affecting the new energy consumption and the contribution and sensitivity of the main factors is of great significance.This paper proposes a new energy consumption influencing factor contribution evaluation model,analyzes the main factors from the contribution metrics; calculates the new energy utilization rate under each boundary condition based on time series production simulation,and establishes a new energy influencing factor sensitive factor calculation model.Taking Xinjiang Power Grid’s new energy consumption as a case,the evaluation method proposed in this paper is used to evaluate the sensitivity of various influencing factors.The analysis shows that various factors such as load growth,increase in delivery capacity,resource characteristics,installed capacity,and access timing all have varying degrees of impact on the consumption of new energy.

Control Technology

Optimal Control of Hybrid Energy Storage System Based on Deep Reinforcement Learning

LI Hong, ZHU Liwei, GUO Zhaohui

2021, 0(11):  42-49.  doi:10.16628/j.cnki.2095-8188.2021.11.007

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Under the islanding operation mode of DC micro-grid,when the photovoltaic output or load changes suddenly,the DC bus voltage fluctuates greatly.To stabilize the DC voltage,hybrid energy storage system charges and discharges quickly,but traditional proportional integral (PI) control is difficult to achieve good control effect.Therefore,an optimal control method based on deep reinforcement learning is proposed.Firstly,the nonlinear characteristics of DC voltage control are analyzed; the deep reinforcement learning algorithm framework and learning process based on input/output data are given.The state space,action space,reward function and neural network are designed to realize the optimal control of DC/DC converter in hybrid energy storage system.Finally,the simulation in DC micro-grid system shows that the proposed method can reduce the DC bus voltage fluctuation and improve the stability of the system compared with PI control.

Self-Energy Storage Back-to-Back VSC-MTDC Control Strategy Based on Virtual DC Generator

SUN Jian, ZHOU Jianhua, GE Le, XIAO Xiaolong, SU Wei

2021, 0(11):  50-57.  doi:10.16628/j.cnki.2095-8188.2021.11.008

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The self-energy storage back-to-back VSC-MTDC system can cause large DC bus voltage fluctuations when the power suddenly changes.In order to enhance the coordinated control capability of the self-energy storage back-to-back VSC-MTDC,a self-energy storage back-to-back VSC-MTDC improved voltage margin control strategy based on virtual DC generator is proposed.The energy storage DC/DC adopts virtual DC generator control in one adjustment process,the setting method of time parameters in the secondary regulation process of energy storage unit is given,this paper also establishes a coordinated working mechanism between the energy storage and each port under several typical operating conditions to improve the dynamic adjustment capability of the system power and the dynamic stability of the DC bus voltage.Finally,a simulation analysis of various operating conditions of the system was carried out to verify the effectiveness of the proposed coordinated control strategy.

Optimization of Hybrid Energy Storage Strategy for Electric Vehicle Based on Super Capacitor

ZHANG Chao, ZHANG Xin, XIE Zhanhong

2021, 0(11):  58-66.  doi:10.16628/j.cnki.2095-8188.2021.11.009

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With the development of electrical vehicle (EV),shortcomings like low charging and discharging speed,large voltage fluctuation and short lifespan of battery become particularly prominent.Aimed at these shortcomings,a hybrid energy storage scheme for EV based on super capacitor (SC) is proposed,and its control strategy is optimized.Taking advantage of fast charging discharging rate of SC,it can quidely respond and compensate the motor transient power,so as to the bus voltage fluctuation and the frequency of the transient battery charging and discharging are reduced,the service life of battery is prolonged.Besides,current feedforward strategy is introduced into the conventional PI strategy to further increase the response speed.The hybrid energy storage system and the motor control system are simulated,the results show that the DC bus voltage variation is effectively limited and the energy quality is improved by the proposed hybrid energy system based on the proposed optimized control scheme through all working modes of EV.

Converting Technology

Parameter Optimization Design of LLC Resonant Converter

MA Chuangming, HUANG Haihong, CHANG Wenjing

2021, 0(11):  67-72.  doi:10.16628/j.cnki.2095-8188.2021.11.010

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LLC resonant converter topology has the advantages of simple structure,high efficiency,high power density,easy integration,etc.,and is widely used in medium and high power DC power supply.However,the resonant process is complex.The basic topology of one-way LLC resonant converter is adopted,and the optimization design method with clear LLC resonant parameters is proposed.The experimental waveforms of underresonant and over-resonant under open-loop debugging are obtained by the experimental prototype.The rationality and universal applicability of the resonant parameter optimization design are verified by the realization of ZVS of the primary side switch tube and ZCS of the secondary side rectifier tube and DC gain.

Zero Ripple High Gain Combined Sepic Converter Based on Coupled Inductor

ZHANG Zhong, XU Yuzhen

2021, 0(11):  73-79.  doi:10.16628/j.cnki.2095-8188.2021.11.011

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High-gain DC-DC converter is an important part of new energy generation grid connection.In order to obtain higher voltage gain,a zero ripple high gain combined Sepic converter based on coupled inductor is proposed.The basic Sepic topology is improved and intergrated to form the new combined Sepic topology,and to further enhance the converter voltage gain,a coupled inductor is introduced to eventually achieve a larger voltage gain with a smaller duty cycle.Through the reasonable configuration of the two coupled inductor and parameters,zero ripple of the input current is achieved approximately.An experimental prototype with 48 V input voltage,400 V output voltage and 100 W rated power is built.The experimental results are consistent with the theoretical results,which verifies the correctness of the theoretical analysis.

Design of Self-driven Synchronous Rectification for Flyback Converter

ZHANG Henghao, SONG Haoyi, HUANG Chao

2021, 0(11):  80-84.  doi:10.16628/j.cnki.2095-8188.2021.11.012

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Flyback converter is widely used as low power switching power supply.The efficiency of flyback converter is greatly improved with the introduction of synchronous rectification technology.Based on the principle of self-driven synchronous rectification technology,an improved voltage self-driven synchronous rectification circuit of flyback converter is presented.The design scheme is verified by experiments.

Application

Exploration and Application of Voiceprint Recognition of Power Transformer Based on Artificial Intelligence and Data Driving

ZHANG Chenchen, DING Guocheng, LI Jianlin, ZHEN Chao, ZHAO Haoran, HUANG Wenli

2021, 0(11):  85-89.  doi:10.16628/j.cnki.2095-8188.2021.11.013

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Sound and vibration are the direct carriers of mechanical information.The promotion of vibro-acoustic detection technology provides an effective means for the state evaluation of the main equipment of the power grid and the diagnosis of mechanical defects.The development of artificial intelligence technology provides unprecedented opportunities for intelligent diagnosis of power grid main equipment based on voiceprint detection.This paper analyzes the vibro-acoustic signal of the main transformer and clean the initial voiceprint data of the transformer through multi-event detection technology,which applies artificial intelligence and data-driven algorithms to extract and mine the voiceprint characteristics of the equipment in different operating conditions,as well as extracting the corresponding relations between the high active value and the voiceprint of the transformer and explores effective ways to characterize its operating status.