Advanced Materials Research Vols. 986-987

Abstract: In energy-saving control process of large-scale-scale intelligent electromechanical device, it is need to consume non-essential energy. To reduce energy consumption, energy-saving design method is proposed based on adaptive linear genetic algorithms. According to theory of adaptive particle swarm optimization, optimal particle is searched in the global domain, which provides basis for energy-saving control of large-scale-scale intelligent electromechanical device. According to adaptive linear genetic theory, energy-saving control model of large-scale intelligent electromechanical device is built to complete energy-saving control. Experimental results show that algorithm can effectively reduce energy consumption and obtain satisfactory results.

Abstract: Batteries have been widely used in the residential electric systems. This paper firstly analyzes the characteristics and feasibility of using the battery to participate in Demand Response (DR) programs. Secondly, the load characteristics in the two different kinds of battery systems are studied, including the power battery of electric bicycles and the battery which are used as the standby power for communication systems and computer systems. Thirdly, this paper studies the DR implementation method of reducing peak and filling valley and related impact on power grid load.

Abstract: Protection equipment in intelligent substation includes Merging Unit, protection equipment and Intelligent Terminal. At present, the status of the intelligent electronic device in intelligent substation protection system is still lack of effective monitoring means. According to the characteristics that substation area protection can obtain current information of all circuits in substation through GOOSE network, a protection system conditioning monitoring relay named PSCMR is designed in this paper. Based on the principle of current differential, PSCMR can accurately identify the abnormal condition or malfunction of Merging Unit or Electronic Current Transformer and realize condition monitoring of intelligent electronic device in protection system.

Abstract: For the specific requirements of power quality in the process of oil exploration,this paper designs a distributed intelligent monitoring systems,including oilfield power quality monitoring center and single oil well monitoring terminal.Among them,Single well terminal hardware is composed of high precision meter chip ATT7022C and ARM9 processor, it can complete the accurate measurement of the electrical parameters.The monitoring center is designed with LabVIEW as the carrier of the power quality comprehensive platform.Using ethernet for data transmission between the terminal and monitoring center. The results show that the system is comprehensive, it can effectively detect multiple power quality parameters and harmonic variation of the grid side,and also can provide technical support for oilfield power quality monitorng automation.

Abstract: . a secure and stable operation of power grid will provide critical assurance for sustainable development of society and economy. Through power grid dispatching auxiliary decision-making system, key information could be obtained from various information sources of the control center such as energy management system, security and stability control system and safety production information system. In case that accident occurs, this intelligent auxiliary decision-making system will provide full assistance to dispatcher with dealing with accidents by starting failure diagnosis function and producing project for coping with accidents. Accelerate transformation of accident handling style from empirical style to analytical and intelligent handling style to improve technical level of sensing of power grid operation status, risks assessment, failure diagnosis and dispatching.

Abstract: The existence of a large number of multicast flooding data in the process level of smart substation,causes serious influence on the real-time performance and reliability of network.Through the exchange principle of Ethernet,the forwarding process of second-layer multicast in network is introduced. Combined with the application in intelligent substation and some experimental data, through in-depth analysis of the 802.1Q VLAN isolating broadcast domain,setting static multicast to change the static MAC address table ,and GMRP to change the multicast information on Ethernet switch through the interactive protocol data, the multicast flooding suppression method is illustrated. And based on the practical engineering situation, the three kinds of methods are compared from the characteristics of debugging operation and maintenance convenience and reliability of intelligent equipment,then the technology route recommendation is given.

Abstract: This paper introduces the current research status of primary frequency regulation and AGC control strategy. Firstly, some important parameters about primary frequency regulation are introduced. Secondly, describes the development on the theory of AGC. Thirdly, the basic concept of CPS and ACE were briefly described, and then the difference between CPS and former A1/A2 standard were compared. Finally, outlook on the coordination between AGC control strategies and primary frequency regulation.

Abstract: Photovoltaic (PV) generation is widely used to solve energy shortage and environment problem. Since the output current of the solar cell will change with the sunlight irradiation, the power of the solar cells are not stable, so there is a need of a storage equipment connected to the PV system. With the characteristics of high efficient energy storage and quick response of the power exchange, the superconducting magnetic energy storage (SMES) can be used to meet the balance between the grid and the PV. A SMES and PV subsystem are connected together with the DC bus, which have less power electronics elements and can control power quality efficiently than linked with the AC bus. This hybrid system is composed of a DC/AC converter on the grid side, a DC/DC converter with the PV arrays, and a DC chopper with the superconducting magnet. A detailed model of the hybrid system is built with MATLAB/SIMULINK. Simulation results with and without SMES connected to the grid-connected photovoltaic system are presented, compared, and analyzed. The results of simulation demonstrate that the SMES system can maintain the DC bus as a constant value which can contribute to the stability and reliability of the grid-connected PV system.

Abstract: SHEPWM technique applicable to multi-level voltage inverter via Walsh function can be solved by linear equations instead of nonlinear transcendental equations. This method don't need a large number of initial values, it’s suitable for online calculation because of its advantages such as high speed calculation and high-accuracy. For the traditional SHEPWM technique based on Walsh function has modulation index restricted problem. This paper proposes a multilevel SHEPWM technique, which Combined Walsh function with multi-band modulation technique. Through the analysis of multi-level multi-band SHEPWM voltage waveform based on Fourier series transform, summarized the multi-level multi-band SHEPWM nonlinear equations when modulation index changed from 0 to 1, and solved the problem with on-line control calculating and modulation index expanding by Walsh function transform. Take five-level inverter as an example, according to the values obtained and considering some equations have several solutions under certain modulation index, using the MATLAB/SIMULINK software do simulation research. The result confirmed that the multi-level multi-band SHEPWM technique based on Walsh function transform is correct and practical.

Abstract: In this paper, 10KW three-phase three-level photovoltaic grid-tied inverter is applied as hardware platform. Considering the insufficiency of PV arrays power output and low overall efficiency due to grid voltage falls asymmetrically, P-R current controller is used to provide unsymmetrical positive and negative sequence current to the grid so that low voltage ride through (LVPT) in photovoltaic inverter can be achieved. Through the implement of experiments, it is well proved that the requirement of LVPT when the grid voltage falls asymmetrically can be met by applying the solution proposed in this paper.