The features of big data technology are big volume, numerous data types, high business value and fast handling speed. Energy Internet is the advanced stage of the combined development of information communication and energy electric technologies, and its main feature is the gradual integration of the two technologies infrastructures. For energy intermet, there are not only numerous information quantities and information categories, but also higer real-time requirements of information. So it is obvious that big data analysis technology has a broad application prospect in Energy Internet. This article makes an overview on big data analysis technology in the big data processing platform and the current research situation of related algorithms, and lists the typical application scenes and research projects in Energy Internet.

This paper introduces the latest progress of IEC 61968 standards as well as relevant national standards, industrial standards and enterprise standards in China. Based on the analysis of the problems of the interoperation tests conducted so far, a new interoperation framework is proposed to be constructed through three steps, i.e.,standardization design based on IEC 61968, test and operation management,which consists of five interoperation layers,i.e.,business, function, information, communication, and component layer.The technology and methodology of the three steps are in focus in order to realize “plug and play” of any link of the interoperation framework, and thus to enhance the power system interoperability.

Grid segmentation is an effective technique to improve the performance of multi-infeed HVDC systems. To study the performance improvement of different kinds of grid segmentation techniques in real power grids, the planning scheme of Guangdong Power Grid in 2030 is taken as an example, traditional LCC-HVDC (line-commutated converter HVDC) segmentation method, VSC-HVDC (voltage source converter HVDC) segmentation method and dynamic segmentation method are applied to the single-corridor interconnection schemeand double-corridor interconnection scheme respectively. The power grid’s performances are calculated and compared from three aspects: multi-infeed effective short-circuit ratio, impact of AC faults on DC systems, and short-circuit current control. Results show that different grid segmentation techniques have different impacts on the real power grid’s performance: the VSC-HVDC segmentation method performs better in all three aspects; the dynamic segmentation method is effective in controlling short-circuit current to a certain extent; the traditional LCC-HVDC segmentation method is effective both in reducing the short-circuit curent and in limiting the maximum number of DC system having commutation failure in AC faults. As for the the planning scheme of Guangdong Power Grid, the VSC-HVDC segmentation method improves the grid performance better than other methods under the double-corridor interconnection scheme.

Multi-terminal mode of the receiving ends of HVDC transmission technologies might be helpful for solving the stability problems caused by large HVDC infeed or especially multi-infeed HVDC. This paper introduces the design characteristics of two modes of multi-terminal HVDC: two poles connected to two different AC grids (TPTDG), and parallel type multi-terminals HVDC (MTHVDC). Some results of AC and DC fault simulation analysis by EMTDC are presented. By comparing the two modes’ properties under faults and influences on control protection system and AC grids, some different characteristics are obtained. It is pointed out that the capability of stable operation of HVDC might be affected with any pole of TPTDG connected to weak AC system, and the inverter station will be substatially less affected with transient faults occurred to the other DC line. The different characteristics between the two modes will provide reference for design optimization of large HVDC access.

In order to meet the safety requirement of the step voltage, the electrode site for the conventional horizontal earth electrodes is very demanding, but the vertical earth electrodes can effectively lower the step voltage, and greatly reduce the difficulty of searching the electrode sites. This paper based on the ground electrode of±800 kV Pu’er converter station, designs both the horizontal and vertical programs and calculates the main technical parameters of each scheme. The result shows that only the the vertical earth electrode can meet the design requirement. In view of the advantages of the vertical earth electrode, it will become an important electrode category for converter station.

According to the demand of ice-melting and dynamic reactive power compensation of power grid, a new design scheme for ice-melting device of MMC based on hybrid sub-module is proposed in this paper, in which half-bridge and full-bridge sub-modules arecoordinated. Then, the method of calculating the number of half-bridge and full-bridge sub-modules is introduced for continuously adjusting the DC voltage of ice-melting device, and it can save up to 1/6 power switches compared with full-bridge MMC, and a capacitor voltage balancing strategy for hybrid sub-modules is also proposed. Finally, the simulation model is validated by PSCAD/EMTDC software, the simulation results verify the correctness and validity of the proposed topology and control method.

: A fixed frequency hysteresis current control method based on space voltage vector is proposed for three-phase four-leg APF. In this method, a set of external hysteresis comparator is used to quickly determine the reference voltage region; the reference voltage vector space is divided into four parallelepipeds. Through a set of internal hysteresis comparator, according to the reference voltage location, three phase switches are selected appropriately to control the corresponding phase-to-phase current independently, then the fixed-frequency hysteretic control technology is realized after decoupling. The method also considers error current phase adjustment so that the error current is optimized, the control accuracy is improved, and the stability of the switching frequency is maintained. Finally, PSCAD / EMTDC power transient simulation software is uesd to validae the effectiveness of the method.

Digital physical hybrid simulation is a new technology in today’s power system simulation, and the interface is the core of the hybrid simulation technology. Power interface design for the hybrid real-time simulation of the RTDS and physical model is carried out, and the characteristics of hybrid simulation interface are studied. Technical route for four-quadrant amplifier interface is put forward, therefore the key technical problems of the hybrid simulation interface are solved, and hybrid simulation interface established. Through the hybrid simulation tests of passive physical model and active physical model, and respectively comparing with the pure digital simulation results, the accuracy and stability of the interface are verified. The result provides a reference for the practical application of the hybrid simulation.

As a new type of operation and maintenance mode for transmission lines, helicopter patrol inspection has the advantages of high efficiency, good effect, etc. However, its large-scale application should be based on the premise of safety operation. In this paper, a safety risk assessment model of helicopter inspection is established by using risk matrix, in which the safety risk factors of the whole operation process are analyzed from the aspects of personnel, equipment and environment. The risk value is determined by the risk probability and the consequence severity, and then the risk level of each risk factor can be assessed according to the position of the risk value in the risk matrix. Differentiated risk control measures are proposed to avoid high-risk operations and provide a favorable support to ensure the safety of power grid, operating personnels and equipment.

In view of the fact that the traditional anomaly detecting methods for power equipment do not consider the spatial information of the state data, this paper proposes a method for anomaly detection of state data of power equipment based on spatiotemporal clustering method, which employs historical big data of the equipment state and meteorological environment and makes visualization of the equipment states in process. The detail of the method is as follows: With a sliding window, the time series are divided into a number of subsequences which will be combined with space coordinates to form spatiotemporal data; the available spatiotemporal structure within each time window is discovered using the FCM method, and an anomaly score is assigned to each cluster, whose value determines whether the cluster is anomalous or not ; then the visualization of a propagation of anomalies occurring in consecutive time intervals is realized by using a fuzzy relation formed between revealed structures. At last, the effectiveness of the method is verified by an example.

Partail discharge (PD) of the gas insulated switchgear (GIS) is the outside phenomenon of its insulation defect. In order to study the PD development, an artificial insulation defect model of surface free metal particles on basin-type insulator in an experimental cavity of a 220 kV GIS is set up. The PD development stages under the defect are simulated with step-up voltage method, and the PD signals in each stage are measured based on UHF method. Based on the measured data, the variations of the discharge frequency, the average amplitude of discharge, the total discharge amplitude, and the maximum discharge magnitude are summarized, and it can be concluded that the PD development triggered by the insulation defect of surface free metal particles on the basin-type insulator of GIS can be divided into the initial stage, the developing stage and the dangerous stage. Besides, these stages can be recognized by the discharge characteristic quantity and discharge scattered point maps.

When 10 kV three-core cable needs to load emergency loads in failure or maintenance, the time the cable can resist the over-load before the temperature of cable conductor reaches the maximum temperature is the major and urgent issue for power department. Therefore, taking the 10 kV three-core cables laid in air as research object, a transient thermal circuit model of cable and air media is established, and the heating time constant of 10 kV three-core cables is calculated by simplifying it into a first-order RC transient thermal circuit model. In addition, the emergency time calculation formula for three-core cable laid in air and the emergency heating experiment for cable laid in air under different initial load are put forward. By comparing the empirical data and theoretical data, the reliability of the proposed model and emergency time calculation formula is successfully proved, which provides an important reference to electricity load distribution under emergency and the control of time in cable maintenance.

Under the background of active distribution networks (ADN), different kinds of DERs including “dispatchable” distributed generation, “not-dispatchable” distributed generation, electrical energy storage and demand response based on interruptible load are studied in this paper. Furthermore, a day-ahead active power scheduling model for distribution company is presented for minimizing the overall system operation costs of the following day and the model is solved by means of adaptive particle swarm algorithm. The proposed method is applied to a modified IEEE 33-node distribution system. The results show that the optimal coordination of multiple kinds of DERs can not only proride good power quality, but manage and accommodate DERs more effectively, and thus has the most economic benefits for distribution company.

The concept of power flow betweenness for distribution network is proposed in this paper considering the uncertainties of distributed generations and loads, and is applied to the allocation analysis of soft normally open points (SNOP). On this basis, an integrated distribution network optimal operation model is established by combining network reconfiguration with SNOP to minimize network loss and voltage deviation. This model can realize the comprehensive optimization of the distribution network on multi-time scales. It can not only ensure the power output within a certain margin, but also reduce the reconstruction times. On the modified IEEE33 bus system, the optimal allocation of SNOP, the optimization effect of SNOP combined with network reconfiguration and short-term dynamic adjustment are analyzed. The results show that the SNOP configuration principle based on the power flow betweenness and the integrated optimization model are feasible and effective.