Advanced Materials Research Vols. 614-615

Abstract: The optimal capacity-load-ratio has great significance to the distribution network’s planning. It’s an important technical indicator of Transforming Capacity Adequacy. In this paper, optimal capacity-load-ratio of multi-voltage distribution network is researched. The cost of construction and operation of distribution network is set as the optimization objective and the reserve life of substation is considered as an optimization variable. The impacts of distributed load factor, the safety operation index, the average power factor of transformer and reserve coefficient of load development are all analyzed. In optimization objective, the construction costs, maintenance cost, energy consumption cost, resource consumption cost and residual value are considered respectively. Finally, a local distribution network in the area of East China is taken as the simulation example and the optimal capacity-load-ratio of this distribution network is calculated. The simulation result verifies the effectiveness of the model established in the paper for distribution network planning.

Abstract: This paper shows the technical standards for distributed resources interconnected with grid in China and the other countries all over the world. For USA, the technical standards about DR interconnection with grid is IEEE 1547 series of standards, which include requirements of connection, testing, monitoring, information exchange, island operation and so on for DR. In international, IEEE standards are the main technical specifications for DR, and it has IEC 61850, IEC 63547, IEC 1727 and so on. But in China, the technical standards for DR are mainly composed by enterprise standard. Comparing with the standards in other countries, the standards of DR in China are not perfect.

Abstract: As the existing methods can not effectively identify multiple bad data, this paper presents a method based on grid partition to detect bad data, and then uses partition re-combination method to identify bad data.

Abstract: The electric power system is a specific example among various networks in nature and human society, in which the network flow models and arithmetic can be applied. The node-voltage-based and branch-current-based hybrid electric power network equations are established in this paper, and the reactive power optimization problem is modeled based on the established network equations. It is respectively solved while the reactive power optimization problem is decomposed as two sub-problems, among which a sub-problem is described by quadric minimum cost flow model and another one is expressed by a linear equations. Thereby, the complexity and dimensions of reactive power optimization problem are distinctly reduced due to the two decomposed sub-problems are easy to solve. It is proved that found optimal solution is closed to global by the computational efficiency analysis. The case study is made at IEEE-30 system and it is indicated that proposed approach could improve the computational efficiency of reactive power optimization problem by comparing with traditional optimal power flow arithmetic.

Abstract: When there exist close oscillation modes in power systems, modes instability may occur due to small changes of system parameters. The mechanism of modes instability in power system with close modes is analyzed using perturbation method and Modal Assurance Criterion is presented to measure the modes instability. New England 10-machine system is applied to analyze characteristics of modes instability by perturbing system parameters. The results show that modal interaction is a crucial factor in the modes instability, and the characteristics of modes instability may be different because of the different interaction happened between close modes.

Abstract: The complementary controllers for HVDC transmission systems can be used to improve the power systems stability. A design method of the complementary controller for multi-infeed HVDC transmission systems using singular Perturbation theory is presented in this paper. The simulation result show that the transient stability of AC/DC system can be effectively improved by use of the presented contort strategy

Abstract: The parallel transmission lines on the same tower and six-phase transmission system both have the characteristic of narrow corridor, less occupied fertile soil and large transmission capacity, so they have been widely applied and laid great attention. The WAMS provides a new technical means for the safe and stable operation of six-line transmission system. Based on electrical signals of transmission lines gained from WAMS, this paper uses long line equation to calculate fault current, and analyzes the fault current with six sequence components method. On basis of magnitude and angle characteristic of six sequence components, a theory of fault phase selection for six-line transmission system is proposed. Theoretical analysis and EMTDC simulation tests show that this method is not affected by distributed capacitance and transition resistance, and can correctly select the fault phase at any case of operation mode and fault condition. It can provide effective fault phase selection logic for distance relay protection of six-line transmission system.

Abstract: The substation is one of the most important nodes for the power system voltage control. Its dynamic behavior is usually characterized by the interaction of dynamic load models, describing continues variables governed by differential equations, and of discrete controllers and coordinated logic, describing symbolic variables governed by discrete behaviors, logic rules and switching mechanisms. Therefore, the operation and control of the substation is a typical hybrid dynamic system. To make an effective voltage coordinated control in substation, this paper proposed a hybrid predictive control strategy. First, the discrete-time hybrid automata model was given for describing the hybrid voltage control system in substation. Then, by using the voltage-security control constrain instead of the goal of voltage-security control, the voltage coordinated control problem can be converted to a minimization cost problem on the premise of the voltage-security control, based on the technology of the MPC. And, for the discrete control characteristics and different control delays of multi-controllers, a branch and search algorithm was designed to solve the hybrid predictive control problem. This proposed algorithm is suitable for the voltage predictive control of substation, which have less control variables and different controllers’ delays. Finally, the coordinated controller was designed on Dymola. And the example of BPA test system three generations and ten buses included was given for simulation analysis and the verification by the proposed approach for substation coordinated voltage control. The results of simulation showed that the proposed control strategy in the paper is feasible.

Abstract: Based on the Service Oriented Architecture (SOA) and Enterprise Service Bus (ESB) technology, following the IEC 61968 standards, This paper presents a program of building Distribution System of Information Exchange Bus (IEB); Study on the integration strategy of the Tianjin Eco Park Distribution Automation System (DAS), Dispatching Automation System, Production Management system and Geographic Information System (GIS) etc.; The information exchange between various systems and the specific processes on outage management application rely on the IEB bus was also presented.

Abstract: This paper introduces the design principles for the resistance wave height meter and structure of hardware and software, madding brief elaborate on the functions and realization of each module. The system adopts a compensating lever method to exclude the impact of the solution conductivity on the system measurement results. The excitation source use bipolar pulse voltage, easing the dielectric polarization problem, so that the circuit is further simplified, improves measurement precision.