Abstract:Low-power self-powered equipment has gradually become the mainstream of development with the continuous advancement of Internet of Things technology. Energy storage module based on supercapacitors can be applied to low-power self-powered smart devices, but the self-discharge characteristics of supercapacitors will cause the loss of stored energy and the drop in terminal voltage, which is not conducive to the power consumption of low-power self-powered devices management and measurement. A variable leakage resistance model which is used to analyze the introduced energy storage module is established in this paper. The relevant parameters in the equivalent model are determined through experiments and the self-discharge process of the energy storage module is analyzed by Matlab/Simulink. Finally, the simulation results are fitted with piecewise linearization in order to facilitate subsequent test error correction or mathematical calculations in the future, and the fitted equivalent circuit model is used to predict the voltage of the energy storage module during self-discharge. The voltage variation of the energy storage module predicted by the equivalent model fits well with the experimental data. The work in this paper completes the basical steps for the designation of power management unit and the power consumption measurement in low-power and energy autonomous devices.

Abstract:Battery management system (BMS) is an important part for battery energy storage system to guarantee the safety operation. It is of great significance for the operation and maintenance of the energy storage power station to test the system before the BMS is put into operation. However, there is no test specification and standard for the battery energy storage system BMS in the field of state of charge (SOC) estimation at present. Therefore, this paper establishes a test platform for BMS of battery energy storage system, Thevenin equivalent circuit model based on the information of external characteristics of battery is utilized, and the method of extrapolation of battery multiple discharge curve is used to obtain the open circuit voltage curve of battery. Besides, the dual extended Kalman filter (DEKF) algorithm is proposed to realize the accurate estimation of SOC. By comparing with the EKF method, DEKF method has advantages in convergence speed and SOC estimation accuracy. Under the typical federal urban driving schedule (FUDS) and dynamic stress test (DST) conditions, the SOC error estimated by DEKF method and EKF method is less than 1%. The battery terminal voltage error is within ±10 mV and ±20 mV respectively, and the average absolute error is within ±20 mV respectively 2.7 mV and 3.8 mV.

Abstract:Energy storage is an important component of grid flexible dispatch resources. In addition to responding to the urgent needs of peak shifting and valley filling, the capacity of centralized energy storage (CES) can also exert huge grid backup capacity under the high penetration of new energy. However, under the dual influence of power generation (consumption)plan and its own power constraints, this capability exhibits obvious dynamic characteristics, which brings certain difficulties to accurate assessment. Therefore, a concept of operational viability domain is introduced. Its reserve capacity is analyzed by describing the electricity and power boundaries of CES, a new method is proposed to calculate the reserve capacity of CES operation under a given power generation (consumption) plan. Based on the simulation analysis of an energy storage power station and a provincial power grid, the effectiveness of the method is verified. The results show that taking into account the reserve capacity of energy storage can effectively reduce the abandonment of the system. Furthermore, the possible effects of energy storage electricity capacity ratio, reserve contracts, etc. on dynamic reserve capacity are quantitatively analyzed. The suggestions for further optimization of energy reserve capacity are given.

Abstract:As an energy storage device, supercapacitors are widely used in the industrial field. In order to improve the output characteristics and extend the life of supercapacitor modules, a double voltage balancing technology for supercapacitor module is proposed in this paper, which is based on the requirements of the instantaneous power for future aerospace vehicles. The charge and discharge curves of supercapacitors under constant current conditions are measured to evaluate the characteristics of cells, which reveals their inconsistency. In the constant process of current charging, the double voltage balancing circuit uses the Buck-Boost converter circuit as the main circuit, and the switched resistance circuit acts as a backup circuit. The cell in the module achieves dynamic voltage balance during charging and reaches the rated voltage value at the end of charging without overcharging. The double voltage balancing circuit solves the problem of voltage imbalance caused by the inconsistency of monomers in the supercapacitor module.

Abstract:In response to the increasingly prominent problem of frequency security and stability of the power grid, the rapid response characteristics and the ability of two-way power adjustment of electrochemical energy storage are incorporated into the third defense line for frequency security based on on-site signal response to deal with low frequency caused by high power shortage. Firstly, the functional positioning of electrochemical energy storage in the third defense line for low frequency security is analyzed. A frequency response model of the third defense line for frequency security contained electrochemical energy storage is proposed based on the equivalent model of a single machine with load. The necessity and prerequisites of sub-round actions of electrochemical energy storage are analyzed. And a calculation method for the critical capacity of sub-round actions is proposed. Furthermore, the formulation method of the corrective control strategy is studied. The frequency recovery effect and control cost are used as comprehensive indicators. A weighted optimization model is formed to tune the control volume of each round, considering the operation mode and failure scenarios. Finally, it is verified by the actual power grid analysis that the proposed corrective control strategy has better frequency control effect and adaptability, which is helpful to expand the application scenarios of electrochemical energy storage in the power grid.

Abstract:With large-scale energy storage stations constructed and being in operation, energy storage source effectively promotes power system dynamic regulating performance for its fast and high precision power control characteristics. Firstly, charging and discharging ability of energy storage stations aggregation is analyzed and the aggregation analysis algorithm of subarea division of power grid is proposed. The analysis results provide ancillary decision-marking proposals in fast power control, peak shifting in short time and load trend following. Secondly, it summarizes the control objectives of energy storage stations aggregation according to requirements of active power balance and power flow control for transmission and transformation in subarea division of power grid. It proposes dispatching strategy which includes charging and discharging state convert and power regulation on the basis of state of charge (SOC) for storage stations in equilibrium to calculate regulating volume in order to satisfy the control objectives in close loop. Finally, a case proves that it develops the aggregation and scale advantage of energy storage source, and thus solves problems in dispatching and control for subarea division of power grid.

Abstract:Load fluctuation is an important factor leading to frequency instability. Short-term load forecasting can predict the active power output of the system and suppress the frequency fluctuation effectively. In order to solve the problem of frequency fluctuation after asynchronous connection of Southwest Power Grid, the probability distribution of load fluctuation amplitude in Southwest China is firstly analyzed. Secondly, the load fluctuation probability is incorporated into load forecasting process to improve the forecasting accuracy. Then, based on the load probability distribution characteristics of Southwest Power Grid, a new hybrid algorithm combining back propagation (BP) neural network and support vector regression (SVR) is proposed. BP neural network is used to evaluate the load level, and the load level obtained is used as the selection basis of SVR algorithm training set to predict the load results of the day. Finally, based on the actual load data, the frequency simulation is carried out. The prediction results are compared with the traditional prediction methods without considering the load probability distribution characteristics, which verifies the superiority of the proposed model in prediction accuracy and effectiveness.

Abstract:In the islandedcontrol system of the large scale new energy power generation throughvoltage source converter based high voltage direct current transmission (VSC-HVDC) station in Zhangbei area, the capacity of the converter station at the feed end is less than the total capacity of the pure new energy power source. In order to ensure that the power fluctuation of the converter station will not exceed the limit in a short time, a fast over-limit power control of converter station is designed in this paper, including fallback power control system when exceeding the limit and the emergency virtual frequency control system, so as to effectively pre-control when the power exceeding the converter station and ensure the safety of the converter station. Firstly, the operation data of new energy power generation in Zhangbei area is analyzed, and the short-time fluctuation characteristics of new energy active power in Zhangbei area are obtained. Through probability statistics, the maximum fluctuation rate occurring in a certain time scale is determined, which provides support for the system parameter design. Then, the structure of the power off-limit fallback control system, the process of the new energy power pre-control, the principle of setting key parameters and the principle of calling the new energy execution station for the power fallback are introduced in details. The emergency virtual frequency control system serves as a backup for fallback power control system in case of communication interruption. Finally, the simulation models of the converter station master station and the executive station controller are built on the PSCAD/EMTDC electromagnetic transient simulation platform for verification.

Abstract:The position adjustment of power transformer tap changer is an important means of voltage regulation in the power system. When the tap changer is not in the standard gear, the transformer works under non-standard ratio conditions, and its operating electrical parameters deviate from the rated parameters. The existing non-standard ratio transformer model is difficult to guarantee high accuracy and high calculation efficiency at the same time. Aiming at this problem, an improved Π-1 type non-standard ratio transformer equivalent circuit model is proposed by using the equivalent transformation of the circuit network. The proposed model has the same accuracy as the accurate T-type non-standard ratio transformer model. And it avoids the disadvantage of increasing the number of equivalent nodes which guarantee high computational efficiency. In order to further improve the convergence characteristics of power flow calculation for backward/forward sweep method, an improved Π-2 model with better practicability is derived based on Y-△ impedance network transformation, which increases the practicability of the model. Based on the comparative analysis of simplified 2-bus, modified IEEE 9 and IEEE 300 test cases, the validity and superiority of the proposed model in terms of calculation accuracy, speed and convergence performance are verified.

Abstract:In order to improve the accuracy of short-term load prediction and provide a more powerful guarantee for stable operation of power system, a short-term load prediction method that applies temporal convolutional network (TCN) and gated recurrent unit (GRU) is proposed in this paper. Firstly, training data are divided into two types, namely time series data and non-time series data. Secondly, time series data are selected as the input of TCN model to extract time series features. Then, time series features and not-time series date are input in the GRU model for training. Finally, the trained model is used to predict short-term power load. Based on real load data of an industry in Foshan City, Guangdong Province, the load forecasting ability of TCN-GRU model is verified. By comparing with the prediction effects of other four deep learning models, the proposed model in this paper is verified to have the ability of forecasting much more accurately for short-term load.

Abstract:The probability prediction of wind power is an effective method to analyze the uncertainty of future wind power. To improve the accuracy of wind power probability prediction, a ultra-short-term wind power probability prediction method based on variational mode decomposition (VMD) and improved quantile regression gated recurrent unit (QRGRU) is proposed. Firstly, VMD is used to decompose the original wind power sequence into mode functions with different characteristics. Then, a probability prediction model based on QRGRU is established for each mode function. The network structure constraint is used as the penalty term of the objective function to improve the stability of the QRGRU weights in the iterative correction process. Finally, the predictive value of each mode function is superimposed under different quantile conditions, and the probability density function of future wind power is obtained by using a non-parametric kernel density estimation method. Based on the actual measurement data of a wind farm, a specific calculation example is analyzed. The results show that the proposed method can take the coverage of the interval into account, reduce the width of the interval and perform better predicting results in different prediction steps.

Abstract:For the purpose of improving voltage support capacity of receiving-end power grid and reducing the risk of high voltage direct current (HVDC) continuous commutation failure, this paper presents an optimization method for the operation of multi-dynamic reactive power devices. Firstly, considering the key characteristics of voltage recovery speed and extinction angle of HVDC after faults, the evaluation index of voltage resilience for receiving-end power grid is introduced to measure the voltage recovery ability. Then, taking the maximum voltage resilience as the optimization objective, a mathematical optimization model is established. In this model, the reactive power output of multi-dynamic reactive power devices is treated as the optimization variable, while the steady and transient constraints of power grid are included at the same time. In the end, particle swarm optimization (PSO) method is used for calculating in the proposed model. To testify the correctness of the model, Suzhou southern power grid is utilized to simulated. The result shows that it effectively improves the recovery speed of grid voltage after short-circuit fault and reduces the number of HVDC continuous commutation failure.

Abstract:Load power fluctuation characteristics differ in time and space owing to many influencing factors. It is of great importance to determine the input features for load power modeling. This paper focuses on the feature selection of short-term power models. The purpose of this paper is to find the optimal set from the features including historical load, weather and date. Firstly, maximum information coefficient, recursive feature elimination method based on support vector machine and random forest are used for feature selection respectively. Secondly, the optimal feature set search strategy based on genetic algorithm is proposed according to the contrastive analysis. Finally, the optimal set of input features is finally determined. An example of calculation is carried out based on the bus load data of a 220 kV substation in a certain area. Compared with the load forecasting results of each feature selection method, the effectiveness and accuracy of the proposed feature selection method in short-term load forecasting have been verified.

Abstract:In view of the low measurement redundancy and frequent switch changes in distribution network, it is difficult to identify the correct topology. A topology identification method based on branch active power is proposed. Based on the residual value of active power, he method selects the branches that may be disconnected and obtains several possible topologies. The state estimation is carried out under each possible topology with the same measurement value, and the matching objective function value is calculated. The topology with the highest possibility is found from the set of possible topologies as the trusted topology. This method greatly reduces the solution space of distribution network topology analysis by calculating the branch active power residual value, and introduces the fast power flow direct current method to estimate the state, which improves the calculation efficiency of the algorithm, thus transforming this kind of distribution network topology error detection problem into a distribution network reconfiguration problem with high matching degree of measured values. The example shows that the method is reasonable, effective, fast and simple, and has good adaptability in the case of large measurement error.

Abstract:In order to optimize the capacity allocation of the energy storage system and improve the power supply reliability and economy of the DC micro-grid cluster, a joint optimal allocation method of independent DC micro-grid cluster hybrid energy storage is proposed in this paper, in which each sub-grid is considered as a standby. Firstly, the optimal objective is to minimize the annual cost of the overall investment, operation and maintenance of the DC micro-grid cluster hybrid energy storage, and a hybrid energy storage capacity allocation model is established. Secondly, the configuration cost of hybrid energy storage is further reduced without losing the independence of the configuration of the hybrid energy storage capacity of each sub-micro grid. Finally, taking a double DC micro-grid cluster as an example, the results illustrate the advantage of micro-grid cluster of interconnected power by comparing the independent optimization and configuration of joint optimization.By applying the joint optimal allocation method, it greatly reduces investment cost of hybrid energy storage system and improves the micro-grid cluster of running stability. The superiority of the proposed configuration method is proved with the independent model of DC micro-grid cluster of planning and construction to provide certain scientific basis.

Abstract:In order to stabilize the power fluctuation of the tie line caused by renewable energy system, it usually adopts two kinds of operational modes in the industrial park. One is the integration of all source and load equipment in the park for unified and centralized management, and the other one is the simple interactive operation mode based on electricity demand response. These two operational modes do not tap comprehensively potentials of integrated demand response of multi-energy loads in the park. Based on a detailed analysis of the energy consumption characteristics in the industrial park, this paper proposes a tie-line power control method and establishes a model based on integrated demand response for production tasks, considering energy storage of park, air conditioning load and electric vehicles. The power fluctuation is stabilized by motivating users to respond to load demand, and the method of tie-line power control decreases effectively operating costs and tracking control errors. Taking a battery production industrial park in south China as an example, the results show that the proposed method reduces the economic loss of the park, benefits internal load users and ensures effective tracking of the tie-line power plan.

Abstract:Pulse laser cleaning of porcelain insulator surface pollution will produce strong thermal effect, and the analysis of temperature characteristics in the cleaning process is very important. In this paper, the contaminated porcelain insulator is taken as the research object. By the method of simulation and experiment, the change rule of temperature field under different typical pollution, different pollution water content, different laser energy density and wavelength are studied. The results show that the temperature is directly proportional to the pollution water content, laser energy density and inversely proportional to the laser wavelength, and the laser wet cleaning is more efficient than the dry cleaning. Under the premise of ensuring the thermal stability of insulator ceramic material, the laser energy density is 2.52~3.81 J/cm², and the scanning speed is 1 000 mm/s, which will not damage the insulator base material and can achieve the best cleaning.

Abstract:The growth of electrical tree in cross-linked polyethylene (XLPE) cables is accompanied by the generation of partial discharges (PD), and there is a correlation between the both. The rise time of the PD signal in XLPE with high dielectric strength is short, so the signal amplitude in the super high frequency (SHF, 3~30 GHz) band is large. In this paper, the defect sample based on needle-plate electrode structure and XLPE insulation material is applied. The morphological of electrical tree and SHF PD signals are detected synchronously during the growth of electrical tree at different temperatures and voltages. The effects of voltage and temperature on the growth of electrical tree and SHF PD signals are analyzed and the characteristic correlation between the morphological of electrical tree and SHF PD signals in XLPE is studied. The results indicate that there is a positive correlation between the length and width of electrical tree in XLPE and temperature or voltage. The fractal dimension is usually lower at a lower voltage while it is not significantly changed with higher voltage. There is also a positive correlation between SHF PD signal amplitudes and temperature or voltage. Higher voltage leads to the trend that the amplitude of SHF signal increase firstly and then decreases to a plateau. The frequency of the signal decreases to a certain extent at a lower voltage. A positive correlation between the growth of electrical tree and the amplitude of SHF PD signals is acquired. The frequency of SHF signals also increases with a faster speed of the growth of electrical tree.

Abstract:Ultra high frequency (UHF) partial discharge detection technology has been widely used in on-line monitoring of electrical equipment. However, the calibration of UHF method is still not realized until now, because the influence factors of UHF signal on transfer function are complicated. In order to study the calibration influence factors of UHF partial discharge (PD) detector, the discharge mechanism of typical PD defects is analyzed, and the relative experimental research in propagation characteristics and sensor characteristics of UHF signals are performed. It is concluded that significant difference is found between UHF signal energy and discharge capacity of different discharge source for calibration reliability. The calibration curve of corona discharge and suspended discharge represents the severity of equipment insulation defect more accurately, while the calibration curve of internal air gap discharge and dielectric surface discharge does ineffectively. The distance of UHF signal energy decays to stable period decreases with the increase of frequency, and the decay of UHF signal energy is irrelevant to its frequencies by measuring in different directions. Therefore, in order to calibration the UHF signal, it is necessary to consider the specific discharge type and measurement condition comprehensively. The results provide the favorable reference for further studies to build calibration system of UHF measurement, and promote effective application of UHF method in sensor characteristic fault diagnosis and insulation evaluation of electrical equipment.

Abstract:Due to its tough demands of communication medium for the equivalent communication of intelligent distributed feeder automation (FA), it mainly adopts the optical fiber communication mode based on ethernet passive optical network (EPON) or industrial Ethernet technology. This communication mode requires the laying of expensive fiber optic cable channels, so it is difficult to apply in the old town or line transformation area. By studying the process of intelligent distributed FA fault management and the adaptability of intelligent distributed FA in the wireless communication situation, this paper puts forward an intelligent distributed FA technology based on 4G/5G wireless communication. The method of combining application-layer protocol control with fault handling process is adopted to realize the close cooperation between the communication time index and FA process among terminals. For abnormal situations such as communication interruption, communication delay and packet loss, communication multi-pack. It comples the distributed fault treatment under wireless communication. Through the simulation of the multi-scene test and application in Jinhua, Zhejiang province, it is shown that the proposed algorithm adapts to different conditions of wireless communication and accurately completes fault isolation and non-failure areas recovery. The effectiveness of intelligent distributed FA technology based on wireless communication is verified.

Abstract:The massive access of renewable energy and electric vehicles in the active distribution network (ADN) has brought many challenges to the planning, construction, dispatch and operation of the current distribution network. By comprehensively considering the uncertain factor like source, network and load side, the research and design of the ADN optimization dispatching method have important guiding significance for the actual operation of the distribution network. Firstly, an ADN comprehensive evaluation system is established to measure the optimal dispatch level of ADN from three aspects which are active controllability, active management and active economy. Then, based on the comprehensive evaluation system, a multi-stage optimization method considering the intelligent dispatching system of electric vehicles is proposed. This method only smoothes the fluctuations caused by intermittent power supply and electric vehicles connected to the grid, but also realizes the optimal dispatch of the current distribution network structure and resources. Therefore, the proposed method can be widely used in the day-ahead scheduling of power system to realize the efficient operation and management of ADN.

Abstract:The status of gas insulated switchgear (GIS) determines the reliability of power equipment operation. Partial discharge is one of the important manifestations for various early-stage latent insulation failures. The traditional partial discharge pattern recognition method relies on expert experience to select the features. The tradtional methed has the disadvantages of strong subjectivity and high uncertainty. To solve this problem, deep learning technology is introduced into the field of partial discharge pattern recognition, which uses convolutional neural network and its extended self-encoding network to extract the characteristics of partial discharge signals and gives full play to the feature extraction ability of self-encoding network. Features are connected with classical classifiers, realizing the organic combination of traditional machine learning method and deep learning method. The basic parameters extraction, statistical feature calculation and discharge type identification of partial discharge signals are realized. The experimental results show that the features extracted by the proposed method significantly improve the classification accuracy and efficiency of partial discharge compared with the traditional artificial features, which has broad engineering application prospects.

Abstract:Partial discharge (PD) detection and recognition are of great significance to the condition monitoring of gas-insulated switchgear (GIS). Metallic particles defects are a type of defect that are easy to occur in GIS. The study focuses on the development process of PD creeping discharge induced by metallic particles in GIS. A GIS simulation experiment platform which is set up according to the actual operating conditions of GIS is employed for this. Step up method is applied to study the PD of metallic particles. The discharge pattern of various stages is measured by pulse current method, meanwhile the characteristic parameters which can characterize the severity of PD effectively are extracted. Intensified CCD (ICCD) is also set up to record the evolution process of PD creeping discharge of the metallic particles, meanwhile the development process is divided with K-Means clustering algorithm combined with characteristic parameters. The results indicate that the evolution process of PD creeping discharge induced by metallic particles in GIS is divided into three stages: corona discharge domination, coexistence of corona discharge and surface streamer discharge and surface streamer discharge domination.

Abstract:SF₆ is widely used in electrical insulation equipment due to its excellent electrical properties, but its greenhouse effect is extremely detrimental to the atmospheric environment. In recent years, C₅F₁₀O, as an environmentally friendly SF₆ potential substitute gas, has attracted the attention of researchers around the world. In order to further explore the insulation properties of C₅F₁₀O/Air and C₅F₁₀O/N₂, a gas insulation performance test platform are used to conduct power-frequency breakdown tests under two quasi-uniform electric fields for two gas mixtures under different pressures and different C₅F₁₀O partial pressures. The experimental results show that the insulation strength of C₅F₁₀O mixed gas increases with the increase of gas pressure. Increasing the partial pressure of C₅F₁₀O can also increase the insulation strength of the two types of buffer gases, and the relative increase in insulation strength of N₂ is greater than that of dry air. From the viewpoint of dielectric strength, C₅F₁₀O /Air has more potential to replace SF₆ in indoor low-voltage equipment than C₅F₁₀O /N₂ mixed gas by appropriately increasing the C₅F₁₀O mixed gas pressure and C₅F₁₀O partial pressure.

Abstract:In order to find the reasons why the wind vibration effect of the large single-pile offshore wind power installation is more significant, the pile-soil interaction of the structure is considered using the p-y curve, the principle and characteristics of the wind-structure fluid-structure coupling are theoretically analyzed. The numerical model of the "wind wheel-cabin-tower-foundation" machine model is established by the ADINA software and used to simulate the wind-induced vibration of the whole machine model. The comparative analysis with the on-site monitoring data shows that the numerical modal analysis and field monitoring results is relatively consistent. The numerical analysis of the dynamic response of the wind-induced wind turbine structure considering the fluid-solid coupling effect is close to the on-site monitoring vibration results, and the trend is consistent. The research results show that the whole machine numerical model and the numerical wind tunnel proposed in this paper are reliable and feasible for wind vibration analysis of the whole wind turbine structure, which provides a scientific basis for the structural design and vibration control simulation research of wind power installations, and have certain reference for wind vibration analysis of similar engineering structures.

Abstract:Converter transformer is an important part of HVDC transmission system. There is no grounding point in the AC side of converter valve, but there is grounding point in the DC side. When one phase grounded fault occurs in the valve side of converter transformer, the fault current changes irregularly with the opening and closing of the converter valves, and the sensitivity of converter transformer protection is usually low. In extreme cases, when the neutral point of Y/Y-connected transformer valve side grounded fault occurs, the protection of converter transformer itself can not trip quickly. Based on the structure and operating conditions of converter transformer, the current characteristics of valve side grounded fault are analyzed, and the characteristics of existing protection are analyzed. Based on the principle of zero sequence differential protection and fast zero sequence overcurrent protection, an optimization scheme of existing converter valve side protection is proposed. It is validated by fault record form a converter substation and simulation waveform from RTDS. The results show that the optimization scheme can effectively improve the sensitivity, operating speed and fault location accuracy of the converter transformer protection under the one phase grounded fault in the valve side.

Abstract:Based on the "physical distribution and logical integration" architecture of new generation power grid dispatching and control system, the global analysis and decision-making services are deployed in multiple analysis and decision-making centers of different locations. Multi-active technology is introduced to ensure the stable and reliable operation of the system and achieve multi-center load balancing. The implementation of global load diversion mechanism based on scenario and service state in the multi service environment is introduced, which can complete the service access diversion and quickly detect the center failure and complete the service access center switching according to the characteristics of the new generation power grid dispatching control system. The problem is solved that the traditional multi center load diversion mechanism under the C/S architecture of the control system can not be applied to the new generation of power grid dispatching control system, and the switch is slow when the center fails. It realizes that the client access can be divided according to the application service distribution. Fast switch is applicable to the application that all centers provide peer-to-peer services, and also supports the application that provides master/slave services.

Abstract:As concentrating solar power (CSP) is equipped with heat storage, it has good regulation performance and the ability to regulate across the day. CSP units have the ability to replace conventional units, which is called as capacity benefits. Since the benefit of CSP capacity is closely related to factors, such as operation mode and heat storage duration of CSP stations, the benefit evaluating of CSP capacity plays an important role in the future development of CSP. A method for evaluating the benefit of CSP stations on the basis of equal reliability is proposed. It takes into account the effects of peak shaving method, heat storage duration, new energy scale and CSP scale. The production simulation program calculates the system operating status of 8 760 hours throughout the year on a weekly scale, taking into account factors such as unit start-stop, hydro-electrical day-to-day adjustment, pumped-storage day-to-day adjustment and day-to-day adjustment of CSP stations. Finally, the effectiveness of the proposed method is verified by simulations of the actual power grid in the northwestern region, which shows that CSP stations have capacity benefits.

Abstract:The construction of the domestic electricity retail market starts relatively later than that of many developed countries. The retail electricity prices and package plans are still immature and need to be further improved. Japan, Singapore and China have similar systems of electricity retail market, and have achieved certain achievements in the construction of the above aspects, which provides a reference for the construction of electricity retail market in China. The reform history of the electricity retail market in Japan and Singapore is sorted out, and the changes and current situations of the retail electricity prices and packages for the two countries are compared and analyzed after the retail market is fully liberalized. Futhermore, combined with the actual situation of well-established retail market in Yunnan, aspects of the market reforms, retail packages, retail electricity prices, retailers and online businesses in the construction of retail markets in Japan and Singapore are analyzed. Suggestions such as gradually liberalizing the retail market, launching joint packages, and constructing network platform are put forward in order to provide reference for the improvement and development of electricity retail market in China.