Voltage stability issues in a distribution grid with large scale PV plant (original) (raw)
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Impact of the solar photovoltaic (PV) generation on long-term voltage stability of a power network
2017 IEEE Innovative Smart Grid Technologies - Asia (ISGT-Asia)
Power system voltage stability is of paramount importance to maintain a secure and reliable power network with high penetration of renewables. This paper investigates the impact of the solar photovoltaic (PV) generation on long-term voltage stability of a power network. Long-term voltage stability is investigated using the Nordic-32 bus test network comprised of dynamic models of automatic voltage regulators (AVRs), overexcitation limiters (OELs) and on-load tap changing (OLTC) transformers combined with static and dynamic loads. The investigation is conducted using an aggregated solar-PV system operating at voltage control mode under various loading conditions. A systematic approach has been followed for solar-PV integration. The results show that solar-PV systems enhance the long-term voltage stability of a stressed transmission grid when they operate under low loading conditions due to the improved reactive power support provided by solar-PV systems.
Impact of large scale photovoltaic generation on voltage stability in distribution networks
European Journal of Electrical Engineering
This paper investigates the impact of integrating large scale photovoltaic power on voltage stability in radial distribution networks. Detailed modeling of the photovoltaic systems is presented. The study is based on bifurcation diagrams of photovoltaic generation, load flow analysis, short circuits, photovoltaic farm disconnections and loading conditions. Maximum penetration levels of solar photovoltaic generation are examined using bifurcation diagrams. The study considers is a utility 53 buses radial distribution network. Several aspects are presented and discussed. RÉSUMÉ. L'évolution des réseaux électriques est marquée par des variations continues de leur topologie. En particulier l'intégration des sources renouvelables de plus en plus importantes a soumis ces réseaux à de nouvelles contraintes d'exploitation. A titre d'exemple, les systèmes photovoltaïques (PV) posent de nouveaux problèmes de stabilité aussi bien statique que dynamique, qui ne cessent d'évoluer avec l'accroissement des puissances installées. En effet, l'intégration de ces fermes photovoltaïques influe sur les caractéristiques électriques de fonctionnement du réseau en régime statique, et présente aussi un impact sur son comportement dynamique. Cet article porte sur l'impact d'une intégration massive de l'énergie photovoltaïque sur la stabilité statique et dynamique du réseau de distribution tunisien. Pour cela nous avons mené une étude statique basée sur les diagrammes de bifurcation de tension. Ensuite nous avons entamé le régime transitoire dans un tel système en cas de base et en cas de pénétration photovoltaïque maximale.
International Journal of Emerging Trends in Engineering Research, 2023
Recently, the rise in consumption of electrical energy and power transmission between various utilities has resulted in the emergence of anxieties about the power system's network voltage stability. Additionally, the necessity for power systems to perform in a secure condition has increased due to an increase in load demand globally. Therefore, the use of renewable energy-based distributed generation is growing quickly to help meet electrical demand and disrupt environmental issues caused by the use of fossil fuels. This type of generation can have a positive or negative influence on the stability of the power system. This paper analyzes the effects of distributed PV power integration on the power grid's voltage stability using static techniques. In order to improve efficacy and accuracy, give a complete and in-depth understanding of the problem of voltage stability, and identify the causes of instability, a combination of four different techniques is employed for analysis. Analysis methodologies include modal analysis, sensitivity analysis, PV curve, and QV curve. The analysis of voltage stability is carried out on an IEEE 14-bus system by using NEPLAN software. The simulation results showed that the integration of a renewable energy resource-based distributed solar PV power system into the test system led to a noticeable improvement in stability degree, a decrease in sensitivity of buses, a significant improvement in system MW loading, an enhancement in voltage profile, and a perceptible increase in reactive power margin.
Impact of Distributed Generation on System Stability using PV Curve
2017
There has been growing concern in distribution system regarding impacts of distributed generation (DG) specifically on voltage stability. The key purpose of this paper is to estimate the voltage stability of power systems with increased level of distributed generation resources based on PV curve. In this technique, the stability of power systems is evaluated with increased penetration level of distributed generation resources. The ultimate objective of this paper is studying the impacts of DG units under diverse Penetration level on few problems such as voltage stability, voltage profile, power flow and PV curve for each bus. In this paper IEEE 14 bus system is simulated in PSCAD and load flow is done in MATLAB Index Terms distributed generation(DG),voltage stability, PV curve, penetration level.
"Influence of Photovoltaic System on Voltage Stability of Practical Network
International Journal of Advanced Engineering and Management Research, 2018
Photovoltaic systems are an important part of renewable energy systems. They graw ver quickly nowadays because of advanced technology. This paper focuses on the influence of photovoltaic generations set on voltage stability of power systems. Singular value Decomposition of Jacobean matrix is adopted for voltage stability assessment. Active Participation Factor(APF) of the minimum eigen value mode is used for the placement of photovoltaic generation set. The adopted network is a part of GCC interconnected network. The results show very good improvement of the capability of the adopted power system
Analysis on the voltage stability on transmission network with PV interconnection
Bulletin of Electrical Engineering and Informatics, 2019
Voltage stability means the ability of the power system network to maintain steady-state voltage value at all buses in the system under normal condition and after being subjected to a disturbance. This research highlights the effect of solar photovoltaic (PV) as the subject of disturbance to the network system as this kind of energy source has emerged towards higher level of integration into the national grid. High penetration of solar PV into the grid may cause several issues of stability and security to the system particularly effecting the normal voltage and line overloading. This research is focused on the simulation of power flow to study the transmission network behavior with and without the solar PV interconnection. To accomplish the research objectives, the network system will be modelled in a software known as Power System Simulator for Engineering (PSSE). The simulation result will be discussed and analyzed using Voltage Stability Indices (VSI) to prove and strengthen the ...
Possible Steady State Voltage Stability Analysis of Electric Power System Using PV Curve Analysis
International journal of advanced research in electrical, electronics and instrumentation engineering, 2015
In recent years, voltage instability and voltage collapse have been observed in power systems of many countries. Such problems have occurred even more often in developed countries because of utility deregulation. Currently, voltage security is of major importance for successful operation of power systems. Assessment of voltage security is needed to utilize power transmission capacity efficiently and to operate the system uninterruptedly. In our research work, we study voltage security of on power system of IEEE20 bus system. We assess voltage security of these systems using P-V curve In other words, we compute margins of real power(P) . To achieve what we promise, we first obtain the power-flow solution for the given data by running the power-flow program that we have coded using MATLAB. The solution is taken as the base case. Second, we choose candidate buses at which we incrementally change real power for plotting P-V curves. The candidate buses are of load buses so that P margins...
International Journal of Bifurcation and Chaos, 2021
This research shows a structural voltage stability analysis of a distribution network incorporating large-scale solar photovoltaic power plant. Detailed modeling of the transmission network and photovoltaic systems is presented and a differential-algebraic equations model is developed. The resulting system state and load-flow Jacobian matrix are reorganized according to the type of the bus system in place of the standard injected complex power equations arrangement. The interactions among system buses for loading tests and solar photovoltaic power penetration are structurally scrutinized. Two-bus bifurcations are revealed to be a predecessor to system voltage collapse. The investigation is carried out by using bifurcation diagrams of photovoltaic generation margin, load-flow analysis, short-circuits, photovoltaic farm disconnections and loading conditions. Furthermore, evaluation of voltage stability reveals that the dynamic component of the voltage strongly depends on fault short-circuit capacity of the power system at the bus, where, the solar system is integrated. The overall result, which encompasses the views from the presented transmission network integration studies, is a positive outcome for future grid integration of solar photovoltaic in the Tunisian system. Tunisia’s utilities policies on integration of solar photovoltaic in distribution network is expected to benefit from the results of the presented study. Moreover, given the huge potential and need for solar photovoltaic penetration into the transmission network, the presented comprehensive analysis will be a valuable guide for evaluating and improving the performances of national transmission networks of other countries too.
2019 IEEE PES GTD Grand International Conference and Exposition Asia (GTD Asia)
With the increasing penetration of photo-voltaic (PV) units into electrical grids, particularly in distribution networks (DNs), the concern of short-term voltage instability (STVI) are growing in the presence of induction motor (IM) loads. On the event of unsymmetrical faults, STVI issues could be more complicated as the next-generation PV systems would require negative sequence power injection into the grid in conjunction with positive one. Therefore, this paper comprehensively investigates the impact of negative sequence power on the shortterm voltage stability (STVS) of DNs. The method of characterizing an unbalanced fault and supplementary controls for PV systems are developed. Different case studies are conducted on a balanced IEEE 4 bus and an unbalanced IEEE 13 bus system by injecting different level of negative sequence power considering with and without peak current limitation of the PV converters. It is observed that STVS is likely to be weakened in case of large negative sequence power penetration, while injecting high positive sequence power can cause excessive voltage swell resulting inverter disconnections. Therefore, both positive and negative sequence powers need to be injected optimally to ensure the system's security following a fault.
Voltage stability assessment of grid connected PV systems with FACTS devices
Scientific Reports, 2022
Three static techniques (i.e. Power flow, Continuation Power Flow (CPF) and the Q-V curve) are used to assess the voltage stability of the power grid with a Solar Photovoltaic Generator (SPVG) and FACTS devices under nominal and heavy loading conditions. A static model is proposed for the power system that includes conventional power generation units and SPVGs with FACTS devices. Two models of SPVG were used (i.e., PV-model and PQ-model) to elucidate the effect of the SPVGs on the stability of the voltage under various operating conditions. The best location for FACTS devices was obtained under nominal and heavy load conditions using static techniques. A comparison between series and shunt FACTS devices under nominal and heavy loading conditions was carried out using the three static techniques. The interaction between SPVGs and FACTS devices was detailed in this paper. The proposed approach was tested on the New England 39-bus standard test system, and the results confirmed the effectiveness of the proposed approach under various operating conditions. Voltage stability is the capability of a power grid at a specified initial operating condition to maintain steady voltages at all buses of the network under a disturbance. Voltage instability results in very low voltages in important parts of the network, culminating in partial or total blackout known as voltage collapse 1,2. Renewable energy sources, such as Solar Photovoltaic Generators (SPVGs), play an essential role in providing clean energy and ensuring adquate supply to meet energy demands. SPVGs can also be used to inject reactive power to the grid. However, the presence of SPVG in a network can cause system/voltage instability 3,4 , which makes imperative that voltage stability be accounted for when connecting SPVG generators to the grid. Dynamic and static are two approaches mentioned in the literature for investigating voltage stability of grids. The dynamic analysis techniques were used in 5,6 to confirm that the photovoltaic system can boost the system's power requirements. Hassan et al. 7 conducted a full dynamic study of voltage stability impact on the IEEE 69-bus and IEEE 118-bus distribution grids with SPVGs. In 8 , the long-term voltage stability of the network was improved after combining SPVG and Nordic-32 bus network using the time-domain simulation. However, dynamic analysis methods are time-consuming and require burden computation. Static techniques are regularly used to investigate voltage stability due to their simplicity and reasonable accuracy 9. In 10 , the static characteristics of the SPVG emerging in a power grid was investigated using only the power flow technique. SPVG's performance on voltage stability was modelled in 11 and 12 using 14-bus with three generators test system and the Ontario test system as case studies, respectively. Both investigations utilized only the Continuation Power Flow (CPF) method. The presence of SPVG improved system stability by increasing the loadability boundary. The CPF method used in 13 analyzed the stability of the voltage of grid-connected SPVG power systems under heavy load condition. The Q-V curve method was used by Wang et al. 14 to elucidate the impact of the SPVG on the static voltage stability of China's Qinghai network, while 15 determined the impact of the SPVG on voltage stability boundary in an islanded microgrid using the P-V curve method. It is clear from the literature that the impact of the SPVG on voltage stability was investigated using only one of the static techniques. FACTS devices implementation into the grid provided a significant opportunity to modify alternating current (AC) transmission, boost or decrease the power flow in exact buses, and respond immediately to instability issues 16. The introduction of FACTS device into the power grid improves the stability of the grid 17. Anbarasan and Sanavullah 18 proposed the CPF method for examining the grid at normal and heavy loading conditions. A Static Synchronous Compensator (STATCOM) was installed at the weakest bus in the network, and it was pointed out that the voltage magnitude of the bus improved as long as the reactive power support is connected to the weakest bus. The V-Q sensitivity method was proposed by P.