optimization of two-stage dynamic reactive power in the distribution network considering the photovoltaic system

2021 ◽  
Author(s):  
Yanbin Guo ◽  
Peng Li ◽  
Changxin Yan
Keyword(s):  
Reactive Power ◽  
Distribution Network ◽  
Photovoltaic System ◽  
Two Stage

scholarly journals Two-Stage Active and Reactive Power Coordinated Optimal Dispatch for Active Distribution Network Considering Load Flexibility

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5922
Author(s):  
Yu Zhang ◽  
Xiaohui Song ◽  
Yong Li ◽  
Zilong Zeng ◽  
Chenchen Yong ◽  
...  
Keyword(s):  
Real Time ◽  
Prediction Error ◽  
Reactive Power ◽  
Distribution Network ◽  
Constant Current ◽  
Economic Losses ◽  
Time Varying ◽  
Two Stage ◽  
Active Distribution Network ◽  
Active And Reactive Power

A high proportion of renewable energy connected to the power grid has caused power quality problems. Voltage-sensitive loads are extremely susceptible to voltage fluctuations, causing power system safety issues and economic losses. Considering the uncertainty factor and the time-varying characteristic, a linearized random ZIP model (constant impedance (Z), constant current (I), and constant power (P)) with time-varying characteristics was proposed. In order to improve the voltage quality of the voltage-sensitive loads in the day-here stage in an active distribution network (ADN), a linearized two-stage active and reactive power coordinated stochastic optimization model was established. The day-ahead active and reactive power coordination optimization was to smooth the large voltage fluctuation and develop a reserve plan to eliminate the unbalanced power caused by the prediction error in the day-here optimization. In the day-here real-time redispatch, the voltage was further improved by the continuous reactive power compensation device. Finally, the simulation results on the IEEE-33 bus system showed that the control strategy could better eliminate the unbalanced power caused by the prediction error and obviously improve the voltage of sensitive loads in the real-time stage on the premise of maintaining economic optimality.

scholarly journals Two-Stage Stochastic Programming Scheduling Model for Hybrid AC/DC Distribution Network Considering Converters and Energy Storage System

2019 ◽  
Vol 10 (1) ◽  
pp. 181
Author(s):  
Peng Kang ◽  
Wei Guo ◽  
Weigang Huang ◽  
Zejing Qiu ◽  
Meng Yu ◽  
...  
Keyword(s):  
Wind Power ◽  
Reactive Power ◽  
Distribution Network ◽  
Stochastic Scheduling ◽  
Second Order ◽  
Mixed Integer ◽  
Two Stage ◽  
Dc Distribution ◽  
Scheduling Model ◽  
Second Order Cone

The development of DC distribution network technology has provided a more efficient way for renewable energy accommodation and flexible power supply. A two-stage stochastic scheduling model for the hybrid AC/DC distribution network is proposed to study the active-reactive power coordinated optimal dispatch. In this framework, the wind power scenario set is utilized to deal with its uncertainty in real time, which is integrated into the decision-making process at the first stage. The charging/discharging power of ESSs and the transferred active/reactive power by VSCs can be adjusted when wind power uncertainty is observed at the second stage. Moreover, the proposed model is transformed into a mixed integer second-order cone programming optimization problem by linearization and second-order cone relaxation techniques to solve. Finally, case studies are implemented on the modified IEEE 33-node AC/DC distribution system and the simulation results demonstrate the effectiveness of the proposed stochastic scheduling model and solving method.

scholarly journals Control of Transformerless Inverter-Based Two-Stage Grid-Connected Photovoltaic System Using Adaptive-PI and Adaptive Sliding Mode Controllers

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2546
Author(s):  
Kamran Zeb ◽  
Muhammad Saqib Nazir ◽  
Iftikhar Ahmad ◽  
Waqar Uddin ◽  
Hee-Je Kim
Keyword(s):  
Reactive Power ◽  
Sliding Mode ◽  
Second Harmonic ◽  
Photovoltaic System ◽  
Two Stage ◽  
Adaptive Sliding Mode ◽  
Fast Tracking ◽  
Feedforward Loop ◽  
Active And Reactive Power ◽  
First Case

To enhance the move towards a sustainable society, the solar Photovoltaic (PV) industry and its applications are progressing at a rapid rate. However, the associated issues need to be addressed when connecting PV to the grid. Advanced and efficient controllers are required for the DC link to control the second harmonic ripple and current controllers to inject quality active and reactive power to the grid in the grid-connected PV system. In this paper, DC-link voltage, active power, and reactive power are successfully controlled in stationary reference using Adaptive-PI (A-PI) and Adaptive-Sliding Mode Controller (A-SMC) for a 3 kW single-phase two-stage transformerless grid-connected inverter. A Resonant Harmonic Compensator (RHC)-based Proportional Resonant (PR) controller is employed in the current-controlled loop. The magnitude, phase, and frequency information of the grid voltage are provided by Second-Order General Integral (SOGI)-based PLL that has harmonic immunity, fast-tracking accuracy, and a rapid-dynamic response. MATLAB®/Simulink®/Simscape R2017b were used for the test bench implementation. Two scenarios were considered: in the first case, the input PV power feedforward loop was avoided, while in second case, it was included. The feedforward loop of input PV power improved the overall system dynamics. The results show that the designed controller improves both the steady-state and dynamic performance as compared with a proper-regulated PI-controller. The proposed controllers are insensitive to active and reactive power variations, and are robust, stable, faster, and fault tolerant, as compared to controllers from prior studies.

scholarly journals Two-Stage Linear Three-Phase State Estimation Formulation for Active Distribution Network

2018 ◽  
Author(s):  
Yuntao Ju
Keyword(s):  
Coordinate System ◽  
State Estimation ◽  
Reactive Power ◽  
Distribution Network ◽  
Polar Coordinate System ◽  
Rectangular Coordinate System ◽  
Linear Measurements ◽  
Two Stage ◽  
Linear State ◽  
Node Voltage

Linear state estimation (SE) formulation under a rectangular coordinate system has been proved to be applicable for real-time distribution network management. Micro phasor measurements’ model can be accommodated into this kind of SE easily. However, voltage magnitude, active power and reactive power measurements are transformed to linear measurements with large node voltage error. To cope with this issue, a linear state estimation under a polar coordinate system is adopted at the first stage to obtain accurate enough complex node voltage, and then nonlinear measurements are transformed to be linear with complex node voltage. At the second stage, linear SE under a rectangular coordinate system can be adopted to satisfy more strict network constraints. The proposed two-stage linear SE is validated on balanced 14, 33, 70,84, 119, 135 nodes network and IEEE 13, 34, 37,123 unbalanced test feeders.

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