scholarly journals An efficient generator voltages control method for improvement of voltage-reactive states in transmission network

2008 ◽  
Vol 21 (2) ◽  
pp. 221-232 ◽  
Author(s):  
Dragan Popovic ◽  
Milos Stojkovic
Keyword(s):  
Reactive Power ◽  
Control Method ◽  
Peak Load ◽  
Voltage Control ◽  
Simulation Models ◽  
Transmission Network ◽  
Accurate Definition ◽  
Generator Voltage ◽  
Definition Of ◽  
Load State

This paper presents an efficient generator voltage control method for improvement of voltage-reactive states in transmission networks. This method enables fast and sufficiently accurate definition of generator voltages to realize the favorable voltage-reactive states. In peak load state, this generator voltage control is made to improve the economic operation, e.g. to reduce the active and reactive power losses or to enlarge the reactive reserve of generators. In minimum load state, this voltage control is made to reduce the generator under-excitation states, or to make the favorable redistribution of those under-excitation states. The verification of method proposed is made in context of steady-state and dynamic simulation models, on the examples of realized and perspective states of Serbian transmission network, in own wide environment. .

Distributed Reactive Power-Voltage Control Method of Micro-Grid

2014 ◽  
Vol 986-987 ◽  
pp. 1214-1217
Author(s):  
Yu Wei Li
Keyword(s):  
Reactive Power ◽  
Control Method ◽  
Voltage Control ◽  
Active Power ◽  
Distributed Power ◽  
Output Stability ◽  
Power Rate ◽  
Multi Agent ◽  
Micro Grid ◽  
Generation Power

For micro-grid with multiple distributed power supply, a micro-grid distributed reactive power-voltage control method is proposed in this paper. By introducing active power disturbance, the load reactive power can be distributed in accordance with the distributed generation power rate, which leads to accurate distribution. At the same time, in order to ensure system voltage output stability in the rate, based on consistency and input/output linearization theory, under the distributed power multi-agent network topology, the distributed nonlinear co-droop controller is designed to make up for voltage fluctuation caused by active power disturbance. The simulation results verified the correctness and feasibility of the proposed control method.

scholarly journals Voltage Control Method for Active Distribution Networks Based on Regional Power Coordination

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4364 ◽  
Author(s):  
Ou-Yang ◽  
Long ◽  
Du ◽  
Diao ◽  
Li
Keyword(s):  
Power Control ◽  
Reactive Power ◽  
Control Method ◽  
Voltage Control ◽  
Distribution Networks ◽  
Active Power ◽  
Reactive Power Control ◽  
Safety Issues ◽  
Bus Voltage ◽  
The Relationship

As loads connected to active distribution network (ADN) grow, ADN’s voltage safety issues are becoming more serious. At present, the solution is mainly to build more distributed generation (DG) or to adjust the reactive power in the whole network, but the former needs a lot of investment while the latter requires a large amount of communication equipment and it takes a long time to calculate the adjustment amount of reactive power and to coordinate reactive power compensation equipment. When the loads are heavy, there will still be drawbacks of insufficient reactive power. Therefore, this paper analyzes the relationship between the active power, reactive power, and the voltage in the ADN. Through the autonomous region (AR) division, a voltage control method based on the active power variation and adjustable power in the AR is proposed. According to the relationship between the amount of active power and the adjustable amount active power, the active power control, the reactive power control, and the coordinated control of active power reactive power control are adopted to adjust the DGs’ output to stabilize the bus voltage. The simulation results show that the proposed method can effectively improve the voltage control capability of ADN and can enable it to operate normally under greater power changes. Through the control method in this paper, the communication requirements are greatly reduced and the calculation time is effectively shortened and is more adaptable.

Micro Static Var Compensator for Over-Voltage Control in Distribution Networks with High Penetration of Rooftop Photovoltaic Systems

2016 ◽  
Vol 839 ◽  
pp. 54-58 ◽  
Author(s):  
Piyadanai Pachanapan ◽  
Phudit Inthai
Keyword(s):  
Power Control ◽  
Reactive Power ◽  
Control Method ◽  
Voltage Control ◽  
Distribution Networks ◽  
Static Var Compensator ◽  
Pv System ◽  
Reactive Power Control ◽  
Pv Systems ◽  
Dynamic Voltage

A micro static var compensator (µSVC) is introduced in this work to prevent the over-voltage problems in radial distribution networks with high number of rooftop photovoltaic (PV) connections. The µSVC is aimed to use in the PV system that has the fixed-power factor inverter, which cannot provide the active voltage controllability. The µSVC is a small shunt compensator installed parallel with the PV system and providing the automatic reactive power support to deal with the dynamic voltage variations at the point of common coupling. Two reactive power control methods, Q(P) and Q(V), can be employed into each µSVC depending on the location of PV systems. Moreover, the coordinated reactive power control among µSVCs, without communication system requirement, is presented for enhancing the Volt-Var controllability to the group of PV systems located in the same feeder. The dynamic voltage control performances are examined on simulation in DIgSILENT PowerFactory software. The results showed that the proposed control method can mitigate the rise of voltage level sufficiently.

scholarly journals A Novel VSG-Based Accurate Voltage Control and Reactive Power Sharing Method for Islanded Microgrids

2019 ◽  
Vol 11 (23) ◽  
pp. 6666 ◽  
Author(s):  
Bowen Zhou ◽  
Lei Meng ◽  
Dongsheng Yang ◽  
Zhanchao Ma ◽  
Guoyi Xu
Keyword(s):  
Reactive Power ◽  
Control Method ◽  
Low Voltage ◽  
Voltage Drop ◽  
Reference Value ◽  
Voltage Control ◽  
Synchronous Generator ◽  
Stability Control ◽  
Control Area ◽  
Power Sharing

Islanded microgrids (IMGs) are more likely to be perturbed by renewable generation and load demand fluctuation, thus leading to system instability. The virtual synchronous generator (VSG) control has become a promising method in the microgrids stability control area for its inertia-support capability. However, the improper power sharing and inaccurate voltage control problems of the distributed generations (DGs) in microgrids still has not been solved with a unified method. This paper proposes a novel VSG equivalent control method named Imitation Excitation Control (IEC). In this method, a multi-objective control strategy for voltage and reactive power in a low voltage grid that considers a non-negligible resistance to reactance ratio (R/X) is proposed. With the IEC method, the voltage drop across feeders is compensated, thus the terminal voltage of each inverter will be regulated, which will effectively stabilize the PCC (point of common coupling) voltage and inhibit the circular current. Meanwhile, this method can realize accurate reactive power tracking the reference value, making it accessible for reactive power scheduling. What is more, the reasonability of the IEC model, namely the equivalent mechanical characteristic and transient process inertia support between VSGs and conventional synchronous generators (SG), is illustrated in this paper. Moreover, steady-state stability is proved by the small-signal modeling method, and the energy required by inertia support is given. Finally, the simulation result validates the effectiveness of the proposed method, and it is also demonstrated that the proposed method outperforms the conventional droop control method.

scholarly journals Control of the powerquality for a DFIG powered by multilevel inverters

2020 ◽  
Vol 10 (5) ◽  
pp. 4592
Author(s):  
H. Hachemi ◽  
A. Allali ◽  
B. Belkacem
Keyword(s):  
Vector Control ◽  
Reactive Power ◽  
Control Method ◽  
Simulation Models ◽  
Multilevel Inverters ◽  
Pi Controllers ◽  
Wind Power System ◽  
Stator Flux ◽  
Doubly Fed ◽  
Vector Control Strategy

This paper treats the modeling, and the control of a wind power system based on a doubly fed induction generator DFIG, the stator is directly connected to the grid, while the rotor is powered by multilevel inverters. In order to get a decoupled system of controlfor an independently transits of active and reactive power, a vector control method based on stator flux orientation SFOC is considered: Direct vector control based on PI controllers. Cascaded H-bridge CHBI multilevel inverters are used in the rotor circuit to study its effect on supply power quality. All simulation models are built in MATLAB/Simulink software. Results and waveforms clearly show the effectiveness of vector control strategy. Finally, performances of the system will tested and compared for each levels of inverter.

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