When a new user accesses the CDMA system, the load will change drastically, and therefore, the advanced outer loop power control （OLPC） technology has to be adopted to enrich the target signal interference ratio （S...When a new user accesses the CDMA system, the load will change drastically, and therefore, the advanced outer loop power control （OLPC） technology has to be adopted to enrich the target signal interference ratio （Silt） and improve the system performance. The existing problems about DS-CDMA outer loop power control for multi-service are introduced and the power control theoretical model is analyzed. System simulation is adopted on how to obtain the theoretical performance and parameter optimization of the power control algorithm. The OLPC algorithm is improved and the performance comparisons between the old algorithm and the improved algorithm are given. The results show good performance of the improved OLPC algorithm and prove the validity of the improved method for multi-service.展开更多
This paper proposes the concept and framework of smart operating system based on the artificial intelligence(AI)techniques. The demands and the potential applications of AI technologies in power system control centers...This paper proposes the concept and framework of smart operating system based on the artificial intelligence(AI)techniques. The demands and the potential applications of AI technologies in power system control centers is discussed in the beginning of the paper. The discussion is based on the results of a field study in the Tianjin Power System Control Center in China. According to the study, one problem in power systems is that the power system analysis system in the control center is not fast and powerful enough to help the operators in time to deal with the incidents in the power system. Another issue in current power system control center is that the operation tickets are compiled manually by the operators, so that it is less efficient and human errors cannot be avoided. Based on these problems, a framework of the smart operating robot is proposed in this paper, which includes an intelligent power system analysis system and a smart operation ticket compiling system to solve the two problems in power system control centers. The proposed framework is mainly based on the AI techniques, especially the neural network with deep learning, since it is faster and more capable of dealing with the highly nonlinear and complex power system.展开更多
An outer loop power control algorithm based on triangle norm(t-norm) information fusion technology is proposed in this paper.According to the difference between block error rate and bit error rate with target values,t...An outer loop power control algorithm based on triangle norm(t-norm) information fusion technology is proposed in this paper.According to the difference between block error rate and bit error rate with target values,the membership function calculation and level dividing of the two differences are dealt with.And then t-norm operator is used to fuse the two membership function values to determine the adjustment step-size.The algorithm can acquire the optimal adjustment step-size in the light of the channel status and avoid the overshoot phenomenon of the existing outer power control methods.As a result,the block error rate can converge to the target value quickly.Experiment results verify the excellent property of the algorithm.展开更多
Through a third⁃order mathematical model of grid⁃oriented LCL⁃type converters,this paper analyzes the complicated dynamic characteristics and resonance problems which may influence the system stability.To realize acti...Through a third⁃order mathematical model of grid⁃oriented LCL⁃type converters,this paper analyzes the complicated dynamic characteristics and resonance problems which may influence the system stability.To realize active damping for LCL filters and improve dynamic performance of current regulators,a state space current PI controller is proposed whose parameters can be tuned based on the polynomial equations approach.An extended state observer is integrated with the regulation scheme,where additional sensors are not necessary in contrast with conventional active damping strategies.Synchronous reference frame PLL(SRF⁃PLL)equipped with filter technology is proposed for grid voltage disturbance suppression.This method is then applied to establish a double⁃closed⁃loop power regulator that demonstrates improved performance compared with other controllers.The simulation results are displayed to illustrate the efficiency of the regulation methods.展开更多
This paper demonstrates a new type of sub-synchronous oscillation of the grid-forming(GFM)converter,which occurs at low rather than high power levels.To reveal the intrinsic mechanism,a simplified analytical small-sig...This paper demonstrates a new type of sub-synchronous oscillation of the grid-forming(GFM)converter,which occurs at low rather than high power levels.To reveal the intrinsic mechanism,a simplified analytical small-signal impedance model of the GFM converter is derived.It is found that the reactive power control loop(RPCL)can have a significant impact on the system stability.In particular,the voltage matrix introduced by the RPCL is the key factor causing instability in the GFM grid-connected system at low operating points.Therefore,this paper proposes a control strategy that reshapes the RPCL to counteract the negative effect of the voltage matrix by introducing a q-axis current feedforward,ensuring stable operation at any operating point.Finally,experimental results validate the correctness and effectiveness of the proposed control strategy.展开更多
Integration of inverter-based resources(IBRs)reshapes conventional power swing patterns,challenging the operation of legacy power swing protec-tion schemes.This paper highlights the significant con-sequences of the di...Integration of inverter-based resources(IBRs)reshapes conventional power swing patterns,challenging the operation of legacy power swing protec-tion schemes.This paper highlights the significant con-sequences of the distinctive power swing patterns exhib-ited by grid-forming IBRs(GFM-IBRs).The swing mechanism involving GFM-IBRs is elucidated using an-alytical modeling of GFM-IBRs with various power syn-chronization loops(PSLs).With varying GFM-IBR pen-etration levels and different generator scenarios,the per-formance of power swing protection functions is examined,including power swing blocking(PSB)and out-of-step tripping(OST).Additionally,the IEEE PSRC D29 test system is employed to present power swing protection results in a large-scale power system integrated with synchronous generators(SGs)and IBRs.The results in-dicate that,GFM-IBRs with sufficient voltage support capability can provide positive impact on power swing dynamics,and power swing protection performance can be enhanced by emulating the inertia and droop mecha-nism of SGs and rapidly adjusting the active power output.However,with high penetration levels of GFM-IBRs,OST maloperation may occur in scenarios with inadequate voltage support capability.展开更多
基金the National Natural Science Foundation of China (60532030).
文摘When a new user accesses the CDMA system, the load will change drastically, and therefore, the advanced outer loop power control （OLPC） technology has to be adopted to enrich the target signal interference ratio （Silt） and improve the system performance. The existing problems about DS-CDMA outer loop power control for multi-service are introduced and the power control theoretical model is analyzed. System simulation is adopted on how to obtain the theoretical performance and parameter optimization of the power control algorithm. The OLPC algorithm is improved and the performance comparisons between the old algorithm and the improved algorithm are given. The results show good performance of the improved OLPC algorithm and prove the validity of the improved method for multi-service.
基金supported by State Grid Corporation of China(SGCC)Science and Technolgy Project(SGTJDK00DWJS1700060)
文摘This paper proposes the concept and framework of smart operating system based on the artificial intelligence(AI)techniques. The demands and the potential applications of AI technologies in power system control centers is discussed in the beginning of the paper. The discussion is based on the results of a field study in the Tianjin Power System Control Center in China. According to the study, one problem in power systems is that the power system analysis system in the control center is not fast and powerful enough to help the operators in time to deal with the incidents in the power system. Another issue in current power system control center is that the operation tickets are compiled manually by the operators, so that it is less efficient and human errors cannot be avoided. Based on these problems, a framework of the smart operating robot is proposed in this paper, which includes an intelligent power system analysis system and a smart operation ticket compiling system to solve the two problems in power system control centers. The proposed framework is mainly based on the AI techniques, especially the neural network with deep learning, since it is faster and more capable of dealing with the highly nonlinear and complex power system.
文摘An outer loop power control algorithm based on triangle norm(t-norm) information fusion technology is proposed in this paper.According to the difference between block error rate and bit error rate with target values,the membership function calculation and level dividing of the two differences are dealt with.And then t-norm operator is used to fuse the two membership function values to determine the adjustment step-size.The algorithm can acquire the optimal adjustment step-size in the light of the channel status and avoid the overshoot phenomenon of the existing outer power control methods.As a result,the block error rate can converge to the target value quickly.Experiment results verify the excellent property of the algorithm.
文摘Through a third⁃order mathematical model of grid⁃oriented LCL⁃type converters,this paper analyzes the complicated dynamic characteristics and resonance problems which may influence the system stability.To realize active damping for LCL filters and improve dynamic performance of current regulators,a state space current PI controller is proposed whose parameters can be tuned based on the polynomial equations approach.An extended state observer is integrated with the regulation scheme,where additional sensors are not necessary in contrast with conventional active damping strategies.Synchronous reference frame PLL(SRF⁃PLL)equipped with filter technology is proposed for grid voltage disturbance suppression.This method is then applied to establish a double⁃closed⁃loop power regulator that demonstrates improved performance compared with other controllers.The simulation results are displayed to illustrate the efficiency of the regulation methods.
基金supported in part by Delta Power Electronics Science&Technology Educational Development Program of Delta Group。
文摘This paper demonstrates a new type of sub-synchronous oscillation of the grid-forming(GFM)converter,which occurs at low rather than high power levels.To reveal the intrinsic mechanism,a simplified analytical small-signal impedance model of the GFM converter is derived.It is found that the reactive power control loop(RPCL)can have a significant impact on the system stability.In particular,the voltage matrix introduced by the RPCL is the key factor causing instability in the GFM grid-connected system at low operating points.Therefore,this paper proposes a control strategy that reshapes the RPCL to counteract the negative effect of the voltage matrix by introducing a q-axis current feedforward,ensuring stable operation at any operating point.Finally,experimental results validate the correctness and effectiveness of the proposed control strategy.
基金supported by the Hong Kong Research Grant Council for the Research Project(No.15229421)the PolyU Presidential PhD Fellowship Scheme。
文摘Integration of inverter-based resources(IBRs)reshapes conventional power swing patterns,challenging the operation of legacy power swing protec-tion schemes.This paper highlights the significant con-sequences of the distinctive power swing patterns exhib-ited by grid-forming IBRs(GFM-IBRs).The swing mechanism involving GFM-IBRs is elucidated using an-alytical modeling of GFM-IBRs with various power syn-chronization loops(PSLs).With varying GFM-IBR pen-etration levels and different generator scenarios,the per-formance of power swing protection functions is examined,including power swing blocking(PSB)and out-of-step tripping(OST).Additionally,the IEEE PSRC D29 test system is employed to present power swing protection results in a large-scale power system integrated with synchronous generators(SGs)and IBRs.The results in-dicate that,GFM-IBRs with sufficient voltage support capability can provide positive impact on power swing dynamics,and power swing protection performance can be enhanced by emulating the inertia and droop mecha-nism of SGs and rapidly adjusting the active power output.However,with high penetration levels of GFM-IBRs,OST maloperation may occur in scenarios with inadequate voltage support capability.
