Binglin Li

Research on power IMS communication network updating method

The State Grid Corporation of China has decided to adopt IMS technology to construct next generation of switch network to provide voice and video communication services. Therefore the existing circuit switch system needs to be upgraded or reformed. It introduced the access equipments, then brought out 4 methods to update the existing network. Finally, the construction principle and construction project of the access network managements system are proposed.

Research on power wireless communication special network for IP multimedia subsystem services

With development of smart grid and demand extension of companys own business, wired network of national grid company which now existed, cannot satisfy mobile internet business requirement that related to IMS fixed application extension, such as remote meter automatic reading, HD video surveillance, mobile office, etc. It is needed to choose the right wireless communication technology and rely on the high-speed and reliable wireless network to meet the new business needs of the State Grid Corporation of China. It proposed three kinds of wireless network scheme implementation suggestion, and submitted the proposal for the scheme selection based on the three schemes. Then it proposed a selection scheme of private wireless communication network. Finally, under the trend of informed environment, it analyzed the promotion of IMS related services in the construction of wireless network, and proposed the development strategy about private wireless network structure to carry IMS services.

Design of distributed optical fiber sensing instrument by functionally divided modules

Distributed optical fiber sensing technologies and corresponding instruments have been greatly developed in the recent 30 years. Many instruments such as optical time domain reflectometry (OTDR), Brillouin optical time domain reflctometry (BOTDR), Brillouin optical time domain analyzer (BOTDA), Raman optical time domain reflectometry (ROTDR), coherent optical time domain reflectometry (COTDR), optical frequency domain reflectometry (OFDR) and so on, have been playing important roles in structure health monitoring and other fields needing distributed status parameter sensing. However, these distributed optical fiber sensing instruments produced by different companies or institutes do not follow the same standards and their structure has huge difference. To build a universal structure standard for the distributed optical fiber sensing instruments (OFSI), a concept which adopts functionally divided modules to define OFSI is proposed and its feasibility is discussed. Generally, OFSI can be divided into five functional modules: controller module, pulse generator module, photo-electric module, signal gathering and processing modules and standard processing chassis module. Then the characteristics of OFSI are embodied mostly by the photo-electric modules. The novel method makes full use of the common functional parts and enhances the flexibility of OFSI, which can reduce the cost of OFSI. Additionally, to produce an instrument by functionally divided modules is a technical trend, and it will promote the standardization of OFSI.

Location of lightning stroke on OPGW by use of distributed optical fiber sensor

A new method based on a distributed optical fiber sensor (DOFS) to locate the position of lightning stroke on the optical fiber ground wire (OPGW) is proposed and experimentally demonstrated. In the method, the lightning stroke process is considered to be a heat release process at the lightning stroke position, so Brillouin optical time domain reflectometry (BOTDR) with spatial resolution of 2m is used as the distributed temperature sensor. To simulate the lightning stroke process, an electric anode with high pulsed current and a negative electrode (the OPGW) are adopted to form a lightning impulse system with duration time of 200ms. In the experiment, lightning strokes with the quantity of electric discharge of 100 Coul and 200 Coul are generated respectively, and the DOFS can sensitively capture the temperature change of the lightning stroke position in the transient electric discharging process. Experimental results show that DOFS is a feasible instrument to locate the lightning stroke on the OPGW and it has excellent potential for the maintenance of electric power transmission line. Additionally, as the range of lightning stroke is usually within 10cm and the spatial resolution of a typical DOFS is beyond 1m, the temperature characteristics in a small area cannot be accurately represented by a DOFS with a large spatial resolution. Therefore, for further application of distributed optical fiber temperature sensors for lightning stroke location on OPGW, such as BOTDR and ROTDR, it is important to enhance the spatial resolution.

Health monitoring of electric power communication line using a distributed optical fiber sensor

Optical fiber ground wire (OPGW) is used for both the earth line and communication line in electric power systems. It is important to find an effective to monitor the status of OPGW and diagnose some possible damages. Fault location of the optical fiber transmission line, lightning stroke location and early-warning of ice covering of OPGW are common tasks for OPGW health monitoring and maintenance. As to these issues, Brillouin optical time domain reflectometry (BOTDR) is employed for the health monitoring of OPGW. In experiment, a positive electrode with high pulsed current and a negative electrode are adopted to form a lightning impulse system with duration time of 200ms for simulation of the lightning stroke process, and a tensile force loading apparatus is also constructed to simulate the strain influence of the ice covering on the OPGW. Experimental results demonstrate that the BOTDR can sensitively locate the lightning stroke incidents with the quantity of electric discharging larger than 100C and the strain component has little interference on temperature monitoring as the fiber contained in the OPGW is generally free of strain, and in the ice covering condition the strain feature appears only when the extra tensile force on the OPGW is over 30kN. In addition, the vibration of OPGW does not disturb both the temperature and strain monitoring. As to further applications of distributed optical fiber sensors (DOFS) for the OPGW health monitoring, it is important to enhance its spatial resolution.

A new OTDR based on probe frequency multiplexing

Two signal multiplexing methods are proposed and experimentally demonstrated in optical time domain reflectometry (OTDR) for fault location of optical fiber transmission line to obtain high measurement efficiency. Probe signal multiplexing is individually obtained by phase modulation for generation of multi-frequency and time sequential frequency probe pulses. The backscattered Rayleigh light of the multiplexing probe signals is transferred to corresponding heterodyne intermediate frequency (IF) through heterodyning with the single frequency local oscillator (LO). Then the IFs are simultaneously acquired by use of a data acquisition card (DAQ) with sampling rate of 100Msps, and the obtained data are processed by digital band pass filtering (BPF), digital down conversion (DDC) and digital low pass filtering (BPF) procedure. For each probe frequency of the detected signals, the extraction of the time domain reflecting signal power is performed by parallel computing method. For a comprehensive performance comparison with conventional coherent OTDR on the probe frequency multiplexing methods, the potential for enhancement of dynamic range, spatial resolution and measurement time are analyzed and discussed. Experimental results show that by use of the probe frequency multiplexing method, the measurement efficiency of coherent OTDR can be enhanced by nearly 40 times.

Unified communication and exchanging platform of video monitoring systems used in ultra high voltage gird

Presently, all of local power enterprises mostly have built video monitoring systems, because there were no standards that can be adopted in initial stages, these systems were running independently and cannot be interconnected, so the need of accessing video information between different areas cannot be met. The first problem of interconnection that need to be solved is to unify call signaling and video coding standard, so now, State Grid Cooperation is drafting enterprise criterion of Grid Video Surveillance System and Interfaces part 1:Technical Requirements to solve the troubles of systems interconnection. The article expatiate the construction project of video interconnection according reality of power enterprise.