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 freq...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 reactance.This paper presents details about HVDC power transmission systems and power converter technologies.Issues 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 discussed.Research studies revealed that the energy crisis of countries like Pakistan can be mitigated to a larger extent with the use of HVDC transmission systems.展开更多
Reliability level of HVDC power transmission systems becomes an important factor impacting the entire power grid.The author analyzes the reliability of HVDC power transmission systems owned by SGCC since 2003 in respe...Reliability level of HVDC power transmission systems becomes an important factor impacting the entire power grid.The author analyzes the reliability of HVDC power transmission systems owned by SGCC since 2003 in respect of forced outage times,forced energy unavailability,scheduled energy unavailability and energy utilization eff iciency.The results show that the reliability level of HVDC power transmission systems owned by SGCC is improving.By analyzing different reliability indices of HVDC power transmission system,the maximum asset benef its of power grid can be achieved through building a scientif ic and reasonable reliability evaluation system.展开更多
This paper presents the effect of the high voltage direct current (HVDC) transmission system based on voltage source converter (VSC) on the sub synchronous resonance (SSR) and low frequency oscillations (LFO) in power...This paper presents the effect of the high voltage direct current (HVDC) transmission system based on voltage source converter (VSC) on the sub synchronous resonance (SSR) and low frequency oscillations (LFO) in power system. Also, a novel adaptive neural controller based on neural identifier is proposed for the HVDC which is capable of damping out LFO and sub synchronous oscillations (SSO). For comparison purposes, results of system based damping neural controller are compared with a lead-lag controller based on quantum particle swarm optimization (QPSO). It is shown that implementing adaptive damping controller not only improves the stability of power system but also can overcome drawbacks of conventional compensators with fixed parameters. In order to determine the most effective input of HVDC system to apply supplementary controller signal, analysis based on singular value decomposition is performed. To evaluate the performance of the proposed controller, transient simulations of detailed nonlinear system are considered.展开更多
文摘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 reactance.This paper presents details about HVDC power transmission systems and power converter technologies.Issues 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 discussed.Research studies revealed that the energy crisis of countries like Pakistan can be mitigated to a larger extent with the use of HVDC transmission systems.
文摘Reliability level of HVDC power transmission systems becomes an important factor impacting the entire power grid.The author analyzes the reliability of HVDC power transmission systems owned by SGCC since 2003 in respect of forced outage times,forced energy unavailability,scheduled energy unavailability and energy utilization eff iciency.The results show that the reliability level of HVDC power transmission systems owned by SGCC is improving.By analyzing different reliability indices of HVDC power transmission system,the maximum asset benef its of power grid can be achieved through building a scientif ic and reasonable reliability evaluation system.
文摘This paper presents the effect of the high voltage direct current (HVDC) transmission system based on voltage source converter (VSC) on the sub synchronous resonance (SSR) and low frequency oscillations (LFO) in power system. Also, a novel adaptive neural controller based on neural identifier is proposed for the HVDC which is capable of damping out LFO and sub synchronous oscillations (SSO). For comparison purposes, results of system based damping neural controller are compared with a lead-lag controller based on quantum particle swarm optimization (QPSO). It is shown that implementing adaptive damping controller not only improves the stability of power system but also can overcome drawbacks of conventional compensators with fixed parameters. In order to determine the most effective input of HVDC system to apply supplementary controller signal, analysis based on singular value decomposition is performed. To evaluate the performance of the proposed controller, transient simulations of detailed nonlinear system are considered.
