Advanced Materials Research Vols. 986-987

Abstract: The new generation of smart substation puts forward higher requirements to sensing technology. Based on the needs of these requirements, four kinds of special optical fiber sensing technology in power systems were researched: all-optical current transformer, distributed temperature sensing technology, fiber grating vibration sensing technology and fiber Bragg grating sensing technology. These kinds of optical fiber sensing technology for the new generation of smart substation to enhance its performance were analyzed. Finally, based on the fiber Bragg grating sensing technology, the online oil and winding temperature monitoring system was constructed for the new generation of smart substation.

Abstract: In order to enhance the capacity of elimination of engine exhaust low frequency noise, a set of engine exhaust active noise control system was developed. The system was developed by using MC9S12XS128 MCU, and it is based on the theory of sound wave interference. The system can realize the voice signal acquisition, reverse phase processing and output, and can eliminate engine exhaust low frequency noise. Experimental results showed that the system has good silencing effects on the engine exhaust noise under the steady state.

Abstract: Variable-speed constant-frequency (VSCF) wind farms are gradually becoming a significant proportion of generation in weak grids with constantly increasing penetration rate, and it should certainly take responsibility of the grid frequency and voltage stability. Based on the P-Q performance curve of doubly fed induction generator (DFIG), by introducing static synchronous compensator (STATCOM), this paper presents a coordinated control strategy of active power and reactive power to deal with fault and load disturbance in weak grids. Simulation results show that the proposed coordinated control strategy can effectively improve the frequency and voltage stability of the grids.

Abstract: Conergy three-level NPC topology is often used in grid connected inverter due to its high efficiency, fewer switching devices and better EMI performance. Traditional half-bridge topology can be transformed to Conergy NPC topology by adding bi-direction switches. This paper proposed a novel control strategy for Conergy three-level NPC three phase grid converter with real and reactive power closed-loop controller in the synchronous d-q rotating frame. The power control loop is based on the feed forward decoupling of d-axis and q-axis components of the output current, thus the active and reactive power can be controlled separately. Additionally a proportional-integral controller is added to enhance the robustness of the power controller. Simulation results verify the effectiveness of the proposed strategy.

Abstract: Power transformer oil purifier described in this article is equipment that filters charged transformer oil in running transformers. Transformer oil can be filtered on line to improve performance of the transformer oil. This article analyzes the necessity of the purification and filtration on processing power transformer oil, describes the overall design ideas of oil purifier in line. Through examples, power transformer oil purifier in line is further discussed the steps and precautions in the application. By comparing the power outage transformer oil purifier and oil purifier in line, the superiority and science of oil purifier in line are clarified.

Abstract: For micro-grid with multiple distributed power supply, a micro-grid distributed reactive power-voltage control method is proposed in this paper. By introducing active power disturbance, the load reactive power can be distributed in accordance with the distributed generation power rate, which leads to accurate distribution. At the same time, in order to ensure system voltage output stability in the rate, based on consistency and input/output linearization theory, under the distributed power multi-agent network topology, the distributed nonlinear co-droop controller is designed to make up for voltage fluctuation caused by active power disturbance. The simulation results verified the correctness and feasibility of the proposed control method.

Abstract: This design platform consists of a computer control, signal interface and PLC or IPC and other components. Signal interface consists of analog and digital input and output board composition, these boards are equipped with signal conditioning and terminal board, the input and output to meet industry standards, can be directly connected with the actual computer control system, this article will focus on the signal interface.

Abstract: To increase the flexibility performance of robot dog, dynamic performance matching of power equipment in four-footed robot dog is made. Demand for power and configure in robot dog power equipment is briefly analyzed, improved backward power match between gasoline and pump is presented, power and flow rate match between gasoline and pump is calculated, control strategy based on pump pressure feedback is applied into gasoline engine control in order to save energy. With experimental bench test, experimental results showed that energy saving matching of power equipment can meet the requirement of fast dynamic meditation for robot dog .

Abstract: PV (Photovoltaic) generation output with MPPT (Maximum power point tracking) is unadjustable. In this paper, PV generation is expected to regulate grid frequency. Thus a power tracking control strategy based on feedback frequency instead of MPPT is put forward. The feedback frequency is transferred to controlling unit of DC-DC inverter. The DC bus voltage is adjusted by controlling the duty cycle of DC-DC invertor. A grid-connected PV system with a power tracking control strategy based on feedback frequency and a DC-AC inverter control module are built in MATLAB-Simulink platform. Experiment result indicates that PV generation could regulate grid frequency by the control strategy based on feedback frequency.

Abstract: Facing to the current environment, energy pressure and wind power development at home and abroad, combined with the actual situation of North China Power Grid, this paper analyzes the wind development in North China firstly, and then based on C# language and the Oracle database develops based on B/S mode of wind power monitoring informing system. This system includes monitoring module, wind data mining module, data management module, real-time alarm module, and the user management module, which realized the wind power in North China Grid remote monitoring and statistical analysis of the data, to ensure data consistency.