With the large scale VSC-HVDC projects put into operation,the black start scheme for the power grid to meet the needs of dispatching operation department is urgently needed for the practical project application of the black start based on VSC-HVDC. In this paper, the mechanism of the black start control strategy and the feasibility of the black start with the target network charging are studied. In view of the current control strategy, the voltage and current surge occur in the charging process, which makes the converter trip and black start fail in severe cases. An improved black start control strategy is proposed to optimize the time sequence of the switch closing, and the VSC-HVDC system black start with target network stepping up from zero voltage is achieved. Meanwhile, a black-start simulation model using Yunnan back to back MMC-HVDC system as the external power supply of Yunnan Power Grid/Guangxi Power Grid based on RTDS is built. By using the I/O device connecting the VSC-HVDC control and protection system and the RTDS model, a closing loop simulation platform of power grid black-start system is built. Simulation results verify the effectiveness of the proposed improved strategy.

To study the effect of moisture content on accumulation and dissipation characteristics of space charge in oil-paper insulation under DC fields, polarization depolarization current measurement system and space charge measurement system are built to measure the conductance of oil-paper insulation with different moisture contents under DC electric field, and the space charge distribution during pressurization and short-circuiting processes. Results show that at 0.91% moisture content, the conductivity has a one-dimensional linear relationship with DC electric field, while under 5.21% moisture content it comes to be a quadratic parabolic relation. Besides, the increase of moisture content raises conductance of oil-paper by several orders of magnitude. With the same moisture content, the rise of applied DC electric field can increase the same-polarity space charge accumulated at the electrode. At 0.91% moisture content, as pressurization lasts, the positive space charge accumulated inside oil-paper increases, and the implantation depth of space charge improves. When under water contents of 5.21 %, homogenous space charges accumulated near the cathode transfer to the interior of oil-paper at pressurization process. Under different water content conditions, the ascent of moisture content during pressurization process obviously increases homogenous space charge and induces charge accumulated at electrodes. As moisture content rises, more heteropolar space charges accumulate in oil-paper near electrodes, while the positive space charge accumulated inside oil-paper decreases. And in short-circuit process, the increase of moisture content accelerates the discharge process of oil-paper and inhibits the occurrence of polarity reversal at electrodes..

In order to overcome the existing difficulty in processing huge amount of data obtained by on-line detection, a new method is proposed in this article, where outlier detection algorithm is used to identify abnormal points in the data and obtain statistics pattern of the entire dataset. To satisfy the demand of partial outlier points, local outlier factor algorithm is used and data of transformer winding DC resistance experiment is processed. Outlier points in the dataset are identified successfully. Besides, the huge amount of data obtained by on-line detection is divided into several state parameters, anomaly coefficient is introduced and state parametr outlier algorithm is used to obtain the radar map of the electrical equipment’s fault and state parameter. Statistic pattern of relativity between fault and parameter is studied to provide reference for further equipment repair. This method is also applicable to the abnormal data detection and analysis of other types of transmission and transformation equipment. By applying this method to the test data of substation equipment of Guangxi Power Grid, 10 main transformers with abnormal direct-current(DC) resistor test data and 75 capacitor voltage transformers (CVTs) with abnormal dielectric loss test data were successfully detected. This method may bring positive significance and broad application prospect in promoting the operation and maintenance level of electrical devices.

Visible light image based insulator recognition is one of the most important tasks of intelligent inspection equipmet identification in power grid. Generally, the samples captured from intelligent inspection in power grid are of low availability and contain multi-scenes. These problems greatly limit the application of deep learning in intelligent recognition of power grid equipment. In this paper, a small number of multi-source images are explored and applied in insulator recognition based on deep learning. Firstly, the development process of object recognition algorithm based on deep learning is described. Secondly, three deep learning models for object recognition are emphatically introduced and compared,which are region-convolutional neural network (R-CNN), Fast region-convolutional neural network (Fast R-CNN) and Faster region-convolutional neural network (Faster R-CNN). Finally, through experiments on a hundred magnitude insulator images from different scenes, the usability and robustness of the Faster R-CNN model are verified. The research and experiment in this paper have explored an effective way for the application of deep learning technology in the object recognition of various equipment in power grid.

Typhoon lands on southern coastal area of China in a high frequency, and it can cause great loss of the power grid. At present, the power grid enterprises still lack effective method for typhoon measurement and warning. Typhoon observation on transmission line in coastal area is very necessary for improving the disaster prevention and mitigation ability of power grid, the observation method of typhoon on transmission line level in coastal areas is studied based on laser wind-detecting radar, three-dimensional ultrasonic anemometer and surface strain gauge and other measuring equipments. This method is verified by the pratical measurement of the typhoon “Meranti”, and large amount of measured data of typhoon “Meranti” is achieved. By analyzing the data deeply, the variation law of wind direction and fluctuation characteristics of typhoon “Meranti” is given.

This paper studies an integrated power system simulation platform based on PSD-BPA and PSS®E two kinds of simulation tools, in response to the increasing scale of power grids and the increasing complexity of structures, the large-scale application of power electronic equipment, and the continuous in-depth transformation of power market transactions to the challenge of power system simulation and calculation. The integrated simulation platform mainly includes data management and integrated simulation. It establishes the integrated simulation system structure and functional structure with integrated data sharing as the goal, and describes the platform workflow, implementation scheme, and features. Through the PSS®E user-defined interface, the dynamic model conversion and generalized modeling of conventional equipment in the power system are realized, a unified system simulation model of the integrated simulation platform is formed, and integrated simulation is realized. Combined with the unified model data of a certain regional power grid maintained by the integrated simulation platform, the advantages of the two software’s in their respective data foundations and custom models are exploited, which verifies the availability and flexibility of the integrated simulation platform for custom modeling and simulation of new types of equipment.

Reducing the impact scope of power failure caused by power outage and preserving the power supply should be both taken into account for microgrid emergency energy management after the failure of electricity supply in distribution network. This paper presents an emergency energy management strategy based on robust optimization for commercial building microgrid consisting of photovoltaic-battery system, and controllable loads regulation scheme is proposed after obtaining the inputs of controllable loads, following the principle of “first adjustment, then cutting off”. The proposed strategy embraces the thought of rolling optimization. Besides, based on robust optimization model, weighting factors are introduced to weigh the importance of reducing the impact and preserving power, and uncertainty is set up to adjust the influence of uncertain factors on the problem. Comprehensive results obtained from comparative analysis, sensitivity analysis and uncertainty analysis have shown that the proposed strategy is effective in adjusting the inputs of controllable loads to reach the desired goals by changing weighting factors and uncertainty flexibly. Moreover, real-time charging rate of electric vehicles and real-time ambient temperature of air conditioners can be obtained from controllable loads regulation scheme.

In order to explore the feasibility of using energy storage to promote renewable energy consumption in China Southern Power Grid(CSG) area, and verify the main ways of storing energy to promote renewable energy consumption, the typical configuration, and the effect of operation strategy, firstly, the optimal pilot area from the selected potential areas in CSG is selected. The assessment and verification of the electricity power curtailment are carried out according to various detailed data in the pilot area as well as the energy storage configuration. Then the energy storage investment and investment recovery period are calculated. Finally, the scheme of energy storage for absorbing renewable energy is compared with conventional schemes such as grid transformation and operation mode optimization. Through analysis, it is found that most problems of the curtailment of wind power and photovoltaic power in the CSG area will be alleviated by planning the use of new substations and putting into operation of power transmission and transformation projects. In CSG area, there is no ideal scenario where the energy storage system is competitive to promote new energy consumption. The initial investment of this scheme is huge and the payback period is very long. Energy storage could become competitive when the curtailment of wind power and photovoltaic power is more evenly distributed through a year and has a relatively modest scale, as well as the cost of batteries declines.

Due to the lack of coal, oil and gas, external electricity is one of the important ways for Guangxi to ensure energy supply in the future. Potential external electricity in Guangxi electricity market has different performance because of their different characteristics. Based on the characteristics and needs of Guangxi power system, this paper selects comprehensive and applicable evaluation indexes, and uses two suitable comprehensive evaluation methods which are the comprehensive score method and TOPSIS method to evaluate the competitiveness of different external electricity and alternative power supply in Guangxi electric power market. Some reasonable suggestions for external electricity absorption in Guangxi power system are put forward.