In this paper, a passive neuro-wavelet based islanding detection technique for grid-connected inverter- based distributed generation was developed. The weight parameters of the neural network were optimized by intelli...In this paper, a passive neuro-wavelet based islanding detection technique for grid-connected inverter- based distributed generation was developed. The weight parameters of the neural network were optimized by intelligent water drop （IWD） to improve the capability of the proposed technique in the proposed problem. The proposed method utilizes and combines wavelet analysis and artificial neural network （ANN） to detect islanding. Connecting distributed generator to the distribution net- work has many benefits such as increasing the capacity of the grid and enhancing the power quality. However, it gives rise to many problems. This is mainly due to the fact that distribution networks are designed without any generation units at that level. Hence, integrating distributed generators into the existing distribution network is not problem-free. Unintentional islanding is one of the encountered problems. Discrete wavelet transform （DWT） is capable of decomposing the signals into different frequency bands. It can be utilized in extracting discrimi- native features from the acquired voltage signals. In passive schemes with a large non-detection zone （NDZ）, concern has been raised on active method due to its degrading power quality effect. The main emphasis of the proposed scheme is to reduce the NDZ to as close as possible and to keep the output power quality unchanged. The simulation results from Matlab/Simulink shows that the proposed method has a small non-detection zone, and is capable of detecting islanding accurately within the minimum standard time.展开更多
This paper proposes a new method to allocate the transmission fixed costs among the network participants in a pool-based electricity market.The allocation process relies on the circuit laws,utilizes the modified imped...This paper proposes a new method to allocate the transmission fixed costs among the network participants in a pool-based electricity market.The allocation process relies on the circuit laws,utilizes the modified impedance matrix and is performed in two individual steps for the generators and loads.To determine the partial branch power flows due to the participants,the equal sharing principle is used and validated by the Shapley and Aumann-Shapley values as two preferred game-theoretic solutions.The proposed approach is also applied to determine the generators’contributions into the loads,and a new concept,named circuit-theory-based equivalent bilateral exchange(EBE),is introduced.Using the proposed method,fairly stable tariffs are provided for the participants.Cross-subsidies are reduced and a fair competition is made by the proposed method due to the counter-flows being alleviated compared with the well-known Z-bus method.Numerical results are reported and discussed to validate the proposed cost allocation method.Comparative analysis reveals that the method satisfies all conditions desired in a fair and efficient cost allocation method.Finally,the developed technique has been implemented successfully on the 2383-bus Polish power system to emphasize that the method is applicable to very large systems.展开更多
This paper presents a new solution to the problem of transmission cost allocation to its users.The proposed technique utilizes modified Z-bus theory,equivalent current injection and impedance of the generators and loa...This paper presents a new solution to the problem of transmission cost allocation to its users.The proposed technique utilizes modified Z-bus theory,equivalent current injection and impedance of the generators and loads,and is developed by the equal-sharing as well as the orthogonal projection principle.The procedure is performed in three steps.First,the modified Z-bus theory is used to calculate the contribution of the users into the network bus voltages as well as the branch currents.Then,the equal sharing principle is confirmed by the game theory solutions and is subsequently applied to identify the users’contributions into the branch power flows.After that,the orthogonal projections of the contributions are calculated and the concept of effective contributions is suggested.The proposed methodology provides the percentage shares of the users on the network complex variables,which help to better assess the contributions.A 2-bus and the IEEE 30-bus test system are used to validate the proposed technique.Finally,the proposed methodology is applied to the polish 2383-bus system to emphasize its applicability to large practical systems.展开更多
文摘In this paper, a passive neuro-wavelet based islanding detection technique for grid-connected inverter- based distributed generation was developed. The weight parameters of the neural network were optimized by intelligent water drop （IWD） to improve the capability of the proposed technique in the proposed problem. The proposed method utilizes and combines wavelet analysis and artificial neural network （ANN） to detect islanding. Connecting distributed generator to the distribution net- work has many benefits such as increasing the capacity of the grid and enhancing the power quality. However, it gives rise to many problems. This is mainly due to the fact that distribution networks are designed without any generation units at that level. Hence, integrating distributed generators into the existing distribution network is not problem-free. Unintentional islanding is one of the encountered problems. Discrete wavelet transform （DWT） is capable of decomposing the signals into different frequency bands. It can be utilized in extracting discrimi- native features from the acquired voltage signals. In passive schemes with a large non-detection zone （NDZ）, concern has been raised on active method due to its degrading power quality effect. The main emphasis of the proposed scheme is to reduce the NDZ to as close as possible and to keep the output power quality unchanged. The simulation results from Matlab/Simulink shows that the proposed method has a small non-detection zone, and is capable of detecting islanding accurately within the minimum standard time.
文摘This paper proposes a new method to allocate the transmission fixed costs among the network participants in a pool-based electricity market.The allocation process relies on the circuit laws,utilizes the modified impedance matrix and is performed in two individual steps for the generators and loads.To determine the partial branch power flows due to the participants,the equal sharing principle is used and validated by the Shapley and Aumann-Shapley values as two preferred game-theoretic solutions.The proposed approach is also applied to determine the generators’contributions into the loads,and a new concept,named circuit-theory-based equivalent bilateral exchange(EBE),is introduced.Using the proposed method,fairly stable tariffs are provided for the participants.Cross-subsidies are reduced and a fair competition is made by the proposed method due to the counter-flows being alleviated compared with the well-known Z-bus method.Numerical results are reported and discussed to validate the proposed cost allocation method.Comparative analysis reveals that the method satisfies all conditions desired in a fair and efficient cost allocation method.Finally,the developed technique has been implemented successfully on the 2383-bus Polish power system to emphasize that the method is applicable to very large systems.
文摘This paper presents a new solution to the problem of transmission cost allocation to its users.The proposed technique utilizes modified Z-bus theory,equivalent current injection and impedance of the generators and loads,and is developed by the equal-sharing as well as the orthogonal projection principle.The procedure is performed in three steps.First,the modified Z-bus theory is used to calculate the contribution of the users into the network bus voltages as well as the branch currents.Then,the equal sharing principle is confirmed by the game theory solutions and is subsequently applied to identify the users’contributions into the branch power flows.After that,the orthogonal projections of the contributions are calculated and the concept of effective contributions is suggested.The proposed methodology provides the percentage shares of the users on the network complex variables,which help to better assess the contributions.A 2-bus and the IEEE 30-bus test system are used to validate the proposed technique.Finally,the proposed methodology is applied to the polish 2383-bus system to emphasize its applicability to large practical systems.
