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A Novel Bi-wavelength Method for Accurately Measuring Gain and Noise Characteristics of an Erbium-Doped Fibre Amplifier for Multi-Channel Wavelength Division Multiplexing transmission

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Chinese Physics Letters 2003年第10期20卷 1777-1780页

作者：刘艳格蒙红云袁树忠田建国开桂云董孝义 InstituteofPhysics NankaiUniversityTianjin300071 InstituteofModernOptics NankaiUniversityTianjin300071

Gain and noise figure (NF) are the most important two parameters of an erbium-doped fibre amplifier (EDFA) for a multi-channel wavelength division multiplexing (WDM) transmission system. A simple bi-wavelength method for accurate gain and NF spectrum measurement of EDFA for WDM applications is proposed. A saturating input signal, whose power equals to the sum of all the WDM signal power and whose wavelength is determined by the channel numbers, and the wavelength of the WDM input signals saturates the EDFA in a degree as the same as the WDM signals input. Meanwhile, a small power probe signal scans and measures the gain and the NF value at every wavelength of the WDM input signals. Investigative results by numerical simulation show that the gain and the NF spectra measured by this method have good agreement with the real spectra of the WDM signal input in a large total input power range. The maximum errors of the gain and the NF are less than 0.2 dB and 0.16 dB, respectively, for a 50-channel input case. The method is competent for the accurate gain and the NF spectrum measurement of the fibre preamplifier and the line-amplifier for WDM applications and has the advantages of simplicity, convenience and easy implement.

关键词： Channel numbers noise characteristics transmission systems maximum error ENTERING Gain Wavelength division multiplexing wavelengths

Performance of a 10-Gbit／s transmission System over 1500 km G.652 Fibre Compensated by Cascaded Narrow-Band Chirped Fibre Bragg Gratings

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Chinese Physics Letters 2005年第8期22卷 1944-1947页

作者：刘艳陈勇谭中伟曹继红郑凯宁提纲陈婷董小伟简水生 InstituteofLightwaveTechnology BeijingJiaotongUniversityBeijing100044

We obtain the error-free transmission of an 8 X 10 Gb/s signal over a 1500kmG.652 fibre by means of significantly improving the quality of narrow-band chirped fibre Bragggratings (FBGs). Asymmetric apodization is one of the powerful measures to improve the quality ofgratings. Wavelength-dependent transmission performance is also observed. The experimental resultsindicate that the total in-band local dispersion deviation of the cascaded gratings in each channelcould be a good indicator of the performance degradation tendency at different operatingwavelengths, which further reveals the potential of local dispersion deviation as a performanceevaluating indicator of chirped FBGs.

关键词： Fiber compensated transmission systems Fiber Bragg gratings Narrowband transmission Characteristics Raster processing

Wide area measurements based fault detection and location method for transmission lines

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Protection and Control of Modern Power systems 2019年第1期4卷 53-64页

作者： Wen Fan Yuan Liao Department of Electrical and Computer Engineering University of KentuckyLexingtonKY40506USA

Electric power grids are critical infrastructure for delivering energy from generation stations to load centers. To maximize utilization of assets, it is desirable to increase the power transferred over transmission systems. Reliable protection of transmission systems is essential for safeguarding the integrity and reliability of the power grid. Distance protection is the most widely used scheme for protecting transmission lines. Most existing protection systems use local measurements to make a decision while pilot protection is used in some circumstances. Distance protection may fail under stressed operating conditions, which could lead to cascading faults. This paper proposes a system integrity protection scheme by utilizing wide area measurements. The scheme partitions the system into subnetworks or protection zones and employs current measurements to derive a fault identification vector indicating the faulted zone. Then the fault location is pinpointed based on wide area measurements and network data. The proposed method is able to deal with multiple, simultaneous faults, and is applicable to both transposed and untransposed lines. Evaluation studies based on simulation studies are presented.

关键词： System integrity protection scheme Fault location transmission systems

High Voltage Direct Current (HVDC) transmission: Future Expectation for Pakistan

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CSEE Journal of Power and Energy systems 2019年第1期5卷 82-86页

作者： Kamran Hafeez Shahid A.Khan Electrical Engineering Department CIIT Islamabad campus Pakistan

An HVDC transmission system for bulk power transfer over longer distance offers numerous advantages over an alternating current(AC)transmission system,such as direct integration of networks operating at different frequencies,comparatively low line losses on account of constant current and absence of *** paper presents details about HVDC power transmission systems and power converter *** concerning integration of electrical power generated by alternate sources(i.e.,wind,onshore and offshore)into the national grid of Pakistan using HVDC technology are also *** studies revealed that the energy crisis of countries like Pakistan can be mitigated to a larger extent with the use of HVDC transmission systems.

关键词： HVDC renewable energy transmission systems wind Energy