As power system interconnections become more prevalent, there has been an increase in use of thyristor controlled shunt connected compensation devices for dynamic power compensation and enhancement of real power trans...As power system interconnections become more prevalent, there has been an increase in use of thyristor controlled shunt connected compensation devices for dynamic power compensation and enhancement of real power transmission capacity. In this paper, an enhancement technique of real power transfer capacity of transmission lines is presented. A SVC （static var compensator） is designed and applied to a simple power system for this purpose. Increase in power flow and improvement in bus voltage profile are observed after using the SVC. Stability analysis of the system after experiencing fault as well as consequent fault clearance by time domain analysis has also beeu performed and satisfactory results are obtained.展开更多
This paper presents the model of a SVC （Static VAR Compensator） which is controlled externally by a PI （Proportional Integral） ＆ PD （Proportional Differential） controllers for the improvements of voltage stabil...This paper presents the model of a SVC （Static VAR Compensator） which is controlled externally by a PI （Proportional Integral） ＆ PD （Proportional Differential） controllers for the improvements of voltage stability and damping effect of an on line power system. Both controller parameters has been optimized by using Ziegler-Nichols close loop tuning method. Both single phase and three phase （L-L） faults have been considered in the research. In this paper, a power system network is considered which is simulated in the phasor simulation method ＆ the network is simulated in four steps; without SVC, With SVC but no externally controlled, SVC with PI controller ＆ SVC with PD controller. Simulation result shows that without SVC, the system parameters become unstable during faults. When SVC is imposed in the network, then system parameters become stable. Again, when SVC is controlled externally by PI ＆ PD controllers, then system parameters becomes stable in faster way then without controller. It has been observed that the SVC ratings are only 50 MVA with controllers and 200 MVA without controllers. So, SVC with PI ＆ PD controllers are more effective to enhance the voltage stability and increases power transmission capacity of a power system. The power system oscillations are also reduced with controllers in compared to that of without controllers. So with both controllers the system performance is greatly enhanced.展开更多
With the increasing development of wind power,the scale of wind farms and unit capacity of wind turbines are getting larger and larger,and the impact of wind integration on power systems cannot be ignored.However,in m...With the increasing development of wind power,the scale of wind farms and unit capacity of wind turbines are getting larger and larger,and the impact of wind integration on power systems cannot be ignored.However,in most cases,the areas with a plenty of wind resources do not have strong grid structures.Furthermore,the characteristics of wind power dictate that wind turbines need to absorb reactive power during operation.Because of the strong correlation between voltage stability and systems' reactive power,the impacts of wind integration on voltage stability has become an important issue.Based on the power system simulation software DIgSILENT and combined analysis of actual practice,this paper investigates the impacts of two types of wind farms on voltage stability:namely a type of wind farms which are constituted by constant speed wind turbines based on common induction generators(IG) and another type of wind farms which are constituted by VSCF wind turbines based on doubly-fed induction generators(DFIG).Through investigation the critical fault clearing time is presented for different outputs of wind farms.Moreover,the impacts of static var compensator(SVC) and static synchronous compensator(STATCOM) on transient voltage stability in IG-based wind farms are studied to improve the security and stability of the Jiangsu power grid after the integration of large scale wind power.展开更多
This paper addresses the enhancement of power system stability by simultaneous tuning of synergetic excitation damping controller and SVC （static var compensator）-based damping controllers. Each machine or generator...This paper addresses the enhancement of power system stability by simultaneous tuning of synergetic excitation damping controller and SVC （static var compensator）-based damping controllers. Each machine or generator is considered as a subsystem and its interaction with the remaining part of the system, the SVC inclusive, is modeled as a quadratic function of the active power delivered by the generator. Stable manifold is constructed for each excitation controller and based on that, an effective damping controller is derived. A lead-lag compensator is employed as a supplementary controller for the SVC. PSO （particle swarm optimization） algorithm is effectively utilized to simultaneously tune the parameters for the excitation damping controller（s） and the SVC supplementary controller. The coordination of the controllers effectively dampens the power angle oscillation and regulates the generator terminal voltage when a fault occurs. Simulation results are obtained by using the PAT （power analysis toolbox） for a SMIB （single machine infinite bus） system and a two area power system.展开更多
Power interconnections are becoming increasingly important in various parts of the world, as incentives for power exchange between countries are growing. A current example is that the Baltic Energy Market Interconnect...Power interconnections are becoming increasingly important in various parts of the world, as incentives for power exchange between countries are growing. A current example is that the Baltic Energy Market Interconnection Plan is launched by the European Council. For a variety of reasons, it is desirable to keep transmission corridors as slender as possible, i.e. keeping the number of lines as limited as possible, while still keeping adequate stability and power transmission capacity over the corridor. This is true, no matter whether it concerns a green-field project, or if it is a question of expanding an existing transmission corridor into higher power transmission capability. To achieve this, FACTS （flexible AC transmission systems）, based on state of the art high power electronics, is a highly useful option, from technical, economical and environmental points of view, to increase the utilization and stability of a transmission system or intertie. The paper presents salient design features as well as benefits of recently installed FACTS devices, more specifically SVC （static var compensators） and series capacitors, for enabling or improving cross-border as well as interregional power transfer in a cost-effective and environmentally friendly way.展开更多
文摘As power system interconnections become more prevalent, there has been an increase in use of thyristor controlled shunt connected compensation devices for dynamic power compensation and enhancement of real power transmission capacity. In this paper, an enhancement technique of real power transfer capacity of transmission lines is presented. A SVC （static var compensator） is designed and applied to a simple power system for this purpose. Increase in power flow and improvement in bus voltage profile are observed after using the SVC. Stability analysis of the system after experiencing fault as well as consequent fault clearance by time domain analysis has also beeu performed and satisfactory results are obtained.
文摘This paper presents the model of a SVC （Static VAR Compensator） which is controlled externally by a PI （Proportional Integral） ＆ PD （Proportional Differential） controllers for the improvements of voltage stability and damping effect of an on line power system. Both controller parameters has been optimized by using Ziegler-Nichols close loop tuning method. Both single phase and three phase （L-L） faults have been considered in the research. In this paper, a power system network is considered which is simulated in the phasor simulation method ＆ the network is simulated in four steps; without SVC, With SVC but no externally controlled, SVC with PI controller ＆ SVC with PD controller. Simulation result shows that without SVC, the system parameters become unstable during faults. When SVC is imposed in the network, then system parameters become stable. Again, when SVC is controlled externally by PI ＆ PD controllers, then system parameters becomes stable in faster way then without controller. It has been observed that the SVC ratings are only 50 MVA with controllers and 200 MVA without controllers. So, SVC with PI ＆ PD controllers are more effective to enhance the voltage stability and increases power transmission capacity of a power system. The power system oscillations are also reduced with controllers in compared to that of without controllers. So with both controllers the system performance is greatly enhanced.
文摘With the increasing development of wind power,the scale of wind farms and unit capacity of wind turbines are getting larger and larger,and the impact of wind integration on power systems cannot be ignored.However,in most cases,the areas with a plenty of wind resources do not have strong grid structures.Furthermore,the characteristics of wind power dictate that wind turbines need to absorb reactive power during operation.Because of the strong correlation between voltage stability and systems' reactive power,the impacts of wind integration on voltage stability has become an important issue.Based on the power system simulation software DIgSILENT and combined analysis of actual practice,this paper investigates the impacts of two types of wind farms on voltage stability:namely a type of wind farms which are constituted by constant speed wind turbines based on common induction generators(IG) and another type of wind farms which are constituted by VSCF wind turbines based on doubly-fed induction generators(DFIG).Through investigation the critical fault clearing time is presented for different outputs of wind farms.Moreover,the impacts of static var compensator(SVC) and static synchronous compensator(STATCOM) on transient voltage stability in IG-based wind farms are studied to improve the security and stability of the Jiangsu power grid after the integration of large scale wind power.
文摘This paper addresses the enhancement of power system stability by simultaneous tuning of synergetic excitation damping controller and SVC （static var compensator）-based damping controllers. Each machine or generator is considered as a subsystem and its interaction with the remaining part of the system, the SVC inclusive, is modeled as a quadratic function of the active power delivered by the generator. Stable manifold is constructed for each excitation controller and based on that, an effective damping controller is derived. A lead-lag compensator is employed as a supplementary controller for the SVC. PSO （particle swarm optimization） algorithm is effectively utilized to simultaneously tune the parameters for the excitation damping controller（s） and the SVC supplementary controller. The coordination of the controllers effectively dampens the power angle oscillation and regulates the generator terminal voltage when a fault occurs. Simulation results are obtained by using the PAT （power analysis toolbox） for a SMIB （single machine infinite bus） system and a two area power system.
文摘Power interconnections are becoming increasingly important in various parts of the world, as incentives for power exchange between countries are growing. A current example is that the Baltic Energy Market Interconnection Plan is launched by the European Council. For a variety of reasons, it is desirable to keep transmission corridors as slender as possible, i.e. keeping the number of lines as limited as possible, while still keeping adequate stability and power transmission capacity over the corridor. This is true, no matter whether it concerns a green-field project, or if it is a question of expanding an existing transmission corridor into higher power transmission capability. To achieve this, FACTS （flexible AC transmission systems）, based on state of the art high power electronics, is a highly useful option, from technical, economical and environmental points of view, to increase the utilization and stability of a transmission system or intertie. The paper presents salient design features as well as benefits of recently installed FACTS devices, more specifically SVC （static var compensators） and series capacitors, for enabling or improving cross-border as well as interregional power transfer in a cost-effective and environmentally friendly way.
