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Given the basic data anomalies and significant redundancy in line loss management within distribution networks， a technique for identifying and correcting abnormal line loss data based on segmented regions is proposed. In view of the redundancy of terminal data， a Kalman filter algorithm is employed to fuse terminal redundant data. Then， by traversing the distribution transformers of various line nodes in the distribution network and using local outlier factor （LOF） algorithm， the operational data are detected. Based on the topological relationship of the distribution networks， the Girvan-Newman （GN） algorithm is used to segment the abnormal nodes. By analyzing the neighboring node measurement data and the imbalance index of the segmented regions， the boundary of the regions is dynamically adjusted until the segmented regions meet the estimated observability conditions. The final division result of segmented regions is obtained， and abnormal data are solved using the measurement model， constraint model， and estimation model within the regions. Finally， an example of the 10 kV Shixin line and Shijin line in a province in Northwest China is used to validate the proposed method. The results demonstrate that the proposed method can identify and correct abnormal line loss data within distribution networks.

In view of the current problem of insufficient consideration being taken of the effect of voltage control and the adjustment cost in the voltage control strategy of distribution networks containing photovoltaic (PV) and energy storage (ES), a multi-stage optimization control method considering grouping collaboration is proposed. Firstly, the mechanism by which the access of the PV and ES to the distribution network impacts the node voltage is explored. Then, the unit regulation cost of a photovoltaic inverter and energy storage power is studied. On this basis, the voltage–cost sensitivity is proposed based on the traditional node power–node voltage sensitivity. According to the differences between each group of regulation resources, a multi-stage voltage over-run control strategy based on grouping cooperation is proposed. Finally, the improved 33-node model is taken as an example to verify the correctness and effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

To solve the problem of the large size of traditional industrial frequency phase-shift transformers and the harmonic distortion of multi-pulse wave rectifier systems, this paper proposes a three-stage shunt zigzag power electronic phase-shift transformer based on a double-tap multi-pulse wave rectifier, which combines the power factor correction (PFC) converter with the voltage-type SPWM inverter circuit to form a power electronic converter to realize the frequency boost and power factor correction. Through AC–DC–AC conversion, the frequency of the three-phase AC input voltage is increased, the number of core and coil turns in the transformer is reduced to reduce the size of the phase-shifter transformer, a zigzag structure of the phase-shifter transformer is used to solve the unbalanced distribution of current between the diode bridges, and a passive harmonic suppression method on the DC side is used to generate a loop current by using a group of single-phase rectifier bridges to regulate the input line current of the phase-shifter transformer. The phase-shifted voltage is input into two three-phase diode rectifier bridges to rectify and supply power to the load. Simulation and semi-physical test results show that the proposed method reduces the total harmonic distortion (THD) value of the input current of the phase-shifted transformer to 7.17%, and the THD value of the grid-side input current is further reduced to 2.49%, which meets the harmonic standard and realizes the purpose of power factor correction as well as being more suitable for high-power applications. [ABSTRACT FROM AUTHOR]

With the integration of large-scale wind power clusters into the power system, wind farms play a crucial role in grid reactive power regulation. However, the range of its reactive power remains uncertain, posing challenges in formulating a viable program for regulating reactive power to ensure the safe and cost-effective operation of the power system. Based on this, this paper develops a bi-level reactive power optimization for wind clusters integrating the power grid while considering the reactive capability. Firstly, this paper carries out a refined analysis of the wind power clusters, taking into account the characteristics of different areas to estimate the exact value of the reactive power capability in wind power clusters. Secondly, a bi-level reactive power optimization model is established. The upper-layer optimization aims to minimize active losses and voltage deviation in power system operation, while the lower-layer optimization focuses on maximizing reactive power margin utilization in wind farms. To solve this bi-level optimization model, an improved artificial fish swarm algorithm (AFSA) is employed, which decouples real variables and integer variables to enhance the optimization ability of the algorithm. Finally, the effectiveness of our proposed optimization strategy and algorithm is validated through the simulation results. [ABSTRACT FROM AUTHOR]

The series-type 12-pulse rectifier generates a large amount of harmonics in the AC side current due to the strong nonlinearity of its rectifying diodes, causing serious harmonic pollution to the power grid. This article proposes a series 36-pulse rectifier based on a DC side dual passive frequency-doubling circuit to suppress the AC side current harmonics of a 12-pulse rectifier. The rectifier uses two symmetrical passive pulse multiplication circuits to regulate the circulation in the DC side circuit, increasing the output voltage and current state of the rectifier bridge, thereby increasing the number of pulses in the rectifier from 12 times to 36 times. Firstly, the working principle of the rectifier and the working mode of the dual passive frequency-doubling circuit were analyzed. Secondly, the harmonic suppression mechanism of the rectifier input current was revealed, and the frequency-doubling characteristics of the load voltage were analyzed. Finally, the correctness of the theoretical analysis was verified through a semi-physical platform. The verification and comparison results show that under the optimal conditions of the injecting transformer turns ratio, the DPPC can not only reduce the THD value of the input current by about 1/3 (from 14.87% to 4.78%) but can also increase the fluctuation frequency of the load voltage by 3 times (from 12 to 36), while improving the power quality of the AC/DC side rectifier and achieving the low harmonic operation of the rectifier. The proposed 36-pulse rectifier can effectively suppress harmonics; it has the advantages of simple structure, strong robustness, and high output voltage gain, and it is suitable for medium-voltage and high-voltage high-power rectification applications. [ABSTRACT FROM AUTHOR]

In view of China's "carbon peak, carbon neutral" strategy, especially the important point of reaching the carbon peak by 2035 and achieving socialist modernisation, it is important to select a number of priority end-use energy consumption technology topics to promote the company's technological innovation. Based on the results of the two rounds of the Delphi survey, eight end-use energy consumption technologies with a "dual carbon" focus should be prioritised, namely: virtual power plant technology, electric vehicle technology, impact assessment and costing of carbon emissions and reduction, and carbon dioxide capture and storage technology. The results of the Delphi survey show that R&D investment, policy mechanisms and market viability are the main constraints to the completion of these technologies. In response to these constraints, relevant recommendations are made in terms of funding input, institutional development and market development.

With the development of modern power systems, higher requirements are imposed on relay protection technology. Traditional relay protection and fault diagnosis technologies have been unable to meet the requirements of the continuous development of power systems, and relay protection systems based on artificial intelligence(AI) technology have received increasing attention. Therefore, this document first analyses the weaknesses of traditional broadcast line protection and uses the adaptability and self-learning of artificial intelligence(AI); to propose the concept of protection of a relay line based on AI. In combination with the artificial nervous network, the AI-based relay protection system shall be studied and the experimental model shall be developed. This paper validates it with simulation experiments. The research results show that for the analysis of the ANN test results of the subnetwork, the actual output of the subnetwork is very close to the ideal output, and the error does not exceed 0.2%. The system has good performance and high reliability. [ABSTRACT FROM AUTHOR]

With the improvement of our country's economic level and quality of life, the numbers and scales of highway networks and motor vehicles are constantly expanding, which makes the current road traffic burden more and more serious. As an important means of traffic automation management, license plate recognition (LPR) technology plays an important role in traffic surveillance and control. However, the recognition rate and accuracy of the traditional license plate recognition methods still need to be improved. In the case of poor surrounding environment, it is prone to localization failure, vehicle license plate recognition errors or unrecognizable phenomena. Wavelet transform, as another landmark signal processing method after Fourier transform, has been widely used in the field of image processing. In China, the number of horizontal lines is usually larger than that of vertical lines. If the two vertical boundaries of the license plate can be detected successfully, the four angles of the license plate can be determined efficiently to complete the license plate positioning. In view of the advantages of wavelet transform technology and the characteristics of vehicle license plate, in this paper, a vehicle license plate recognition algorithm based on wavelet transform and vertical edge matching is proposed. The edge of the license plate is detected by wavelet transform technology, and then the license plate is located by vertical edge matching technology. After the location is realized, the characters are segmented by vertical projection method and the characters are recognized by improved BP neural network algorithm. The experimental results show that the proposed vehicle license plate recognition algorithm based on wavelet transform and vertical edge matching performs well in algorithm performance, which provides a good reference for the development of vehicle license plate recognition system. [ABSTRACT FROM AUTHOR]

The structure of materials is closely related to their electrochemical properties. MnMoO 4 materials have good stability as supercapacitors but their specific capacitance performance is not excellent. To improve electrochemical performance of MnMoO 4 , this study conducts secondary hydrothermal treatment in thiourea solution on MnMoO 4 electrode material grown on nickel foam synthesized by traditional hydrothermal method. A more compact S-doped MnMoO 4 electrode material with more oxygen vacancies and higher specific capacitance was obtained. At the current density of 1 A g -1 , the specific capacitance of the composite material reached 2526.7 F g -1 , which increased by 140.9% compared with that of ordinary MnMoO 4 material. The capacitance retention rate of the composite material was 95.56% after 2000 cycles at 10 A g -1 . An asymmetric supercapacitor was fabricated using S-doped MnMoO 4 as the positive electrode, activated carbon as the negative electrode, and 6 mol L -1 KOH solution as the electrolyte. The specific capacitance of the assembled supercapacitor was 117.50 F g -1 at 1 A g -1 , and a high energy density of 47.16 W h kg -1 at the power density of 849.98 W kg -1 was recorded. This method greatly improves the specific capacitance of MnMoO 4 through simple processing, which makes it have great application potential., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)