point of common coupling
Recently Published Documents


TOTAL DOCUMENTS

240
(FIVE YEARS 112)

H-INDEX

11
(FIVE YEARS 4)

Author(s):  
Salman Harasis ◽  
Saher Albatran ◽  
Eyad Almaita ◽  
Khaled Alzaareer ◽  
Qusay Salem ◽  
...  

<p>Controlling weak grid-connected systems is very challenging. In transient, frequency and voltage oscillations may lead to voltage and/or frequency stability problems and finally lead to system collapse. During steady-state operation and at the point of common coupling (PCC), voltage degradation and grid voltage background harmonics restrict the inverter's functionality, reduce the power flow capability and cause poor power quality. With weak grid connection, grid impedance variance will contaminate the voltage waveform by harmonics and augment the resonance, destabilizing the inverter operation. In this paper, complete mathematical modeling is carried out and state feedback-plus-integral control is implemented to support the stabilization of the system. The proposed controller is adopted to provide a smooth transient under sudden load change by controlling the injected grid current under different grid inductance values. Furthermore, the proposed control is used to reduce the order and size of the inverter output filter while maintaining system stability. The proposed control has been compared with the conventional proportional integral (PI) controller under different scenarios to validate its effectiveness and to strengthen its implementation as a simple controller for distributed generator applications.</p>


2022 ◽  
Vol 203 ◽  
pp. 107679
Author(s):  
Oscar Pinzón-Quintero ◽  
Daniel Gaviria-Ospina ◽  
Alejandro Parrado-Duque ◽  
Rusber Rodríguez-Velásquez ◽  
German Osma-Pinto

Author(s):  
Satyavarta Kumar Prince ◽  
Kaibalya Prasad Panda ◽  
Shaik Affijulla ◽  
Gayadhar Panda

Abstract The islanding detection is a major problem for both AC and DC Microgrids. Failure to do so may result in problems such as system instability, increased non-detection zone, out-of-phase reclosing, personnel safety, and power quality deterioration. To address this issue, this paper presents a reliable island identification method for DC Microgrids that employs a Cumulative Sum of Rate of change of Voltage (CSROCOV) to reduce the non-recognition region. The proposed islanding protection scheme employs point of common coupling (PCC) transient signal to detect islands events. The voltage, power, and current sampling are accumulated from the PCC of the distributed generation terminals. The proposed scheme detects islanding in three test cases with varying power mismatching conditions, while non-islanding events are classified as capacitor switching and faults. The system is modelled and simulated in the MATLAB/Simulink environment, then islanding conditions are applied by turning off the main circuit breaker. Simulation results are presented to verify the methodology under different test cases. The robustness of the proposed scheme is also validated against measurement noise.


Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8453
Author(s):  
Ki Ryong Kim ◽  
Sangjung Lee ◽  
Jong-Pil Lee ◽  
Jaesik Kang

This paper proposes an enhanced control strategy for mitigating state-transition oscillations in active and reactive power responses of self-synchronized converter system to secure the islanded power system stability. The self-synchronized converter is well known for “grid-forming” that is able to operate to stand-alone mode (SAM) providing grid voltage and frequency without phase synchronization units. Although the grid-forming (GFM) is self-synchronized, the inherent synchronization principle causes system degradation in which should maintain a point of common coupling (PCC) voltage for critical loads as well as transitions from grid-connected mode (GCM) to SAM and vice versa. Therefore, this paper focuses on resolving the inherent oscillatory issues in GFM self-synchronized converter system (especially adopted ‘synchronverter’ principle), and proposes a control strategy for controllability improvement based on stability analysis for smooth state-transition under islanded power system. The efficacy of the proposed control method is verified through a high-fidelity electromagnetic transient (EMT) simulation with case studies on 30kW synchronverter system and further experimental hardware-in-loop system (HILS) test with Opal-RT (OP-5707) platform.


Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8416
Author(s):  
Yaroslav Shklyarskiy ◽  
Iuliia Dobush ◽  
Miguel Jiménez Carrizosa ◽  
Vasiliy Dobush ◽  
Aleksandr Skamyin

In this article, a method that allows sharing responsibilities for the generation of harmonic currents between the utility and consumers powered by one point of common coupling (PCC) is addressed. For these purposes, mathematical modeling of the power supply system (PSS) with two consumers is carried out in order to introduce new indices using the simplest PSS structure as an example. Two indices are introduced that quantify the consumers’ contribution to the distortion of current and voltage at the PCC and that evaluate harmonic emission from the utility side. Experimental tests are carried out where both linear and nonlinear loads are considered, capacitive loads are taken into account, and harmonic distortions from the utility side are modeled to show the applicability of the indices in a wide range of load types. The experiments confirmed the theoretical results and illustrated that the quantitative assessment of the contributions is unambiguous. It suggests that the proposed criterion could be a reasonable basis for further tax policy on harmonic pollution for each consumer at the PCC and for the utility.


2021 ◽  
Vol 9 (12) ◽  
pp. 1413
Author(s):  
Linda Barelli ◽  
Dario Pelosi ◽  
Dana Alexandra Ciupageanu ◽  
Panfilo Andrea Ottaviano ◽  
Michela Longo ◽  
...  

Among Renewable Energy Sources (RES), wind energy is emerging as one of the largest installed renewable-power-generating capacities. The technological maturity of wind turbines, together with the large marine wind resource, is currently boosting the development of offshore wind turbines, which can reduce the visual and noise impacts and produce more power due to higher wind speeds. Nevertheless, the increasing penetration of wind energy, as well as other renewable sources, is still a great concern due to their fluctuating and intermittent behavior. Therefore, in order to cover the mismatch between power generation and load demand, the stochastic nature of renewables has to be mitigated. Among proposed solutions, the integration of energy storage systems in wind power plants is one of the most effective. In this paper, a Hybrid Energy Storage System (HESS) is integrated into an offshore wind turbine generator with the aim of demonstrating the benefits in terms of fluctuation reduction of the active power and voltage waveform frequency, specifically at the Point of Common Coupling (PCC). A MATLAB®/SimPowerSystems model composed of an offshore wind turbine interfaced with the grid through a full-scale back-to-back converter and a flywheel-battery-based HESS connected to the converter DC-link has been developed and compared with the case of storage absence. Simulations were carried out in reference to the wind turbine’s stress conditions and were selected—according to our previous work—in terms of the wind power step. Specifically, the main outcomes of this paper show that HESS integration allows for a reduction in the active power variation, when the wind power step is applied, to about 3% and 4.8%, respectively, for the simulated scenarios, in relation to more than 30% and 42% obtained for the no-storage case. Furthermore, HESS is able to reduce the transient time of the frequency of the three-phase voltage waveform at the PCC by more than 89% for both the investigated cases. Hence, this research demonstrates how HESS, coupled with renewable power plants, can strongly enhance grid safety and stability issues in order to meet the stringent requirements relating to the massive RES penetration expected in the coming years.


Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8287
Author(s):  
Watcharakorn Pinthurat ◽  
Branislav Hredzak

Unbalanced active powers can affect power quality and system reliability due to high penetration and uneven allocation of single-phase photovoltaic (PV) rooftop systems and load demands in a three-phase four-wire microgrid. This paper proposes a distributed control strategy to alleviate the unbalanced active powers using distributed single-phase battery storage systems. In order to balance the unbalanced active powers at the point of common coupling (PCC) in a distributed manner, the agents (households’ single-phase battery storage systems) must have information on the active powers and phases. Inspired by supervised learning, a clustering approach was developed to use labels in order to match the three-phase active powers at the PCC with the agents’ phases. This enables the agent to select the correct active power data from the three-phase active powers. Then, a distributed power balancing control strategy is applied by all agents to compensate the unbalanced active powers. Each agent calculates the average grid power based on information received from its neighbours so that all agents can then cooperatively operate in either charging or discharging modes to achieve the compensation. As an advantage, the proposed distributed control strategy offers the battery owners flexibility to participate in the strategy. Case studies comparing performance of local, centralized, and the proposed distributed strategy on a modified IEEE-13-bus test system with real household PV powers and load demands are provided.


2021 ◽  
Author(s):  
Simin Pang ◽  
Ruiyuan Jia ◽  
Qihui Liu ◽  
Linlin Wu ◽  
Hui Liu

The phenomenon of three phase voltage imbalance frequently occurs in large-scale new energy grid connected areas in China; in severe cases, a large number of wind turbines will be disconnected from the grid. To solve the problem of the voltage imbalance at the point of common coupling (PCC), analyze the influence of generator parameters change on negative sequence voltage under the background of unbalanced power grid, a modeling method of base-frequency negative sequence impedance of doubly fed induction generator (DFIG) which including phase locked loop (PLL), rotor side converter (RSC) and grid side converter (GSC) is proposed. By establishing the negative sequence equivalent circuit of grid-connected system of DFIG, the relationship between the negative sequence voltage of PCC and the negative sequence impedance of DFIG is listed, and analyzing the sensitivity of control parameters link to base-frequency impedance, the parameter that has great influence on base-frequency negative sequence impedance of PCC is found out. Finally, the accuracy of impedance modeling and sensitivity analysis is verified by simulation studies.


Data in Brief ◽  
2021 ◽  
Vol 39 ◽  
pp. 107681
Author(s):  
Emenike Ugwuagbo ◽  
Adeola Balogun ◽  
Ayobami Olajube ◽  
Osita Omeje ◽  
Ayokunle Awelewa ◽  
...  

2021 ◽  
Author(s):  
Erhan Sezgin ◽  
Anurag Mohapatra ◽  
Vedran S. Peric ◽  
Ozgül Salor ◽  
Thomas Hamacher

<i>The paper has been submitted to PSCC 2022 and is currently awaiting reviews.<br></i><br>This paper proposes and implements, a harmonic analysis algorithm for microgrid Power Hardware-in-the-loop (PHIL) experiments, when the point of common coupling (PCC) voltage cannot be directly wired to the local prosumer controllers due to long distances between them. Using frequency-shifting and filtering ideas, the voltage measurement is converted to magnitude and phase information. This is passed over an asynchronous communication link to another controller, where it is recovered into a waveform after delay compensation. The method allows for accurate power calculations and grid synchronization over distributed prosumer controllers. The proposed method can work at different execution rates depending on real time (RT) workload and is shown to be robust against step changes, harmonics and communication delays. The method is demonstrated with two PHIL experiments at the CoSES, TU Munich lab in grid connected and island mode.


Sign in / Sign up

Export Citation Format

Share Document