scholarly journals Subsynchronous Resonance and FACTS-Novel Control Strategy for Its Mitigation

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Doan Duc Tung ◽  
Le Van Dai ◽  
Le Cao Quyen

The subsynchronous resonance (SSR) is an important problem in the power system, and especially the series compensated transmission lines may cause SSR in the turbine generators, such that it leads to the electrical instability at subsynchronous frequencies and potential turbine-generator shaft failures. Taking the Vietnamese Vungang thermal plants as an example, a shaft failure of Vungang I thermal power unit has occurred on November 24, 2015, due to SSR. The main cause for this failure is a resonance caused by the series capacitors on the 500 kV grid. This paper analyzes the SSR based on the location of shaft cracks and turbine generator mode shape for Vungang I and II thermal power plants. On the basis of that, it develops a novel control strategy for each Flexible AC Transmission system (FACTS) device as the thyristor controlled series compensator (TCSC), static VAR compensator (SVC), and static synchronous compensator (STATCOM). Then they are comparable to one another in order to choose a feasible solution for mitigating the SSR. The effectiveness of the proposed control strategy is verified via time domain simulation of the Vietnamese 500/220 kV transmission system using EMTP-RV and PSS/E programs. The obtained results show that the proposed strategy for SVC can be applied to immediately solve the difficulties encountering in the Vietnamese power system.

Egypt is progressing from a power system with old traditional thermal power stations to a cutting-edge power system with a profoundly productive combined cycle power plants (Siemens 14.4 GW power plants) and an expanding portion of sustainable power sources. By 2022, Egypt intends to produce 20 % of its power from renewables [1]. Benban Solar Park venture is considered as the world's largest solar power plant, with total capacity of about 1.8 GW. The large renewable power stations, especially the solar power plants, have a significant effect on power systems stability due to rapid and large fluctuations in power generation caused by various factors such as the intermittency of solar irradiance, climate change and tripping out of power electronic based converters connected to the system. This paper presents the specialized technical details of the assessment and results to ensure that the Egyptian Transmission System (ETS) is capable to evacuate the renewable power in safe manner under various operating conditions


Author(s):  
M.V. Cherniavskyi

The structure of electricity cost formation for consumers, including depending on the cost of TPP generation, «green» energy and other sources, is investigated, and the main conditions of the efficient regulatory function fulfillment in the power system by thermal power generation in the conditions of Ukraine's course on carbon-free energy are formulated. It is shown that excessive electricity losses in networks and, especially, accelerated increase of the share of «green» generation, much more expensive than nuclear, hydro and thermal, mainly contribute to the growth of electricity costs for non-household consumers and the need to raise tariffs for the population. This accelerated increase directly contradicts the Paris Climate Agreement, according to which plans to reduce Ukraine’s greenhouse gas emissions must be developed taking into account available energy resources and without harming its own economy. The dependences of the specific fuel consumption on the average load and the frequency of start-stops of units are found and it is shown that the increased specific fuel consumption on coal TPPs is an inevitable payment for their use as regulating capacities of UES of Ukraine. In this case, the higher the proportion of «green» generation and a smaller proportion of generating thermal power plants, especially increasing specific fuel consumption. It is proved that in the conditions of growth of the share of «green» generation in Ukraine the share of production of pulverized coal thermal power plants should be kept at the level of not less than 30 % of the total electricity generation. It is substantiated that a necessary condition for coal generation to perform a proper regulatory role in the power system is to introduce both environmental and technical measures, namely — reducing the suction of cold air to the furnace and other boiler elements, restoring condensers and cooling systems, etc. An important factor in reducing the average level of specific fuel consumption is also the reduction of coal burn-out at thermal power plants, where it still remains significant, due to the transfer of power units to the combustion of bituminous coal concentrate. Bibl. 12, Fig. 5, Tab. 5.


Author(s):  
Naraina Avudayappan ◽  
S.N. Deepa

Purpose The loading and power variations in the power system, especially for the peak hours have abundant concussion on the loading patterns of the open access transmission system. During such unconditional state of loading the transmission line parameters and the line voltages show a substandard profile, which depicts exaction of congestion management of the power line in such events. The purpose of this paper is to present an uncomplicated and economical model for congestion management using flexible AC transmission system (FACTS) devices. Design/methodology/approach The approach desires a two-step procedure, first by optimal placement of thyristor controlled series capacitor (TCSC) and static VAR compensator (SVC) as FACTS devices in the network; second tuning the control parameters to their optimized values. The optimal location and tuning of TCSC and SVC represents a hectic optimization problem, due to its multi-objective and constrained nature. Hence, a reassuring heuristic optimization algorithm inspired by behavior of cat and firefly is employed to find the optimal placement and tuning of TCSC and SVC. Findings The effectiveness of the proposed model is tested through simulation on standard IEEE 14-bus system. The proposed approach proves to be better than the earlier existing approaches in the literature. Research limitations/implications With the completed simulation and results, it is proved that the proposed scheme has reduced the congestion in line, thereby increasing the voltage stability along with improved loading capability for the congested lines. Practical implications The usefulness of the proposed scheme is justified with the computed results, giving convenience for implementation to any practical transmission network. Originality/value This paper fulfills an identified need to study exaction of congestion management of the power line.


2016 ◽  
Vol 67 (4) ◽  
pp. 234-245 ◽  
Author(s):  
Goran Knežević ◽  
Zoran Baus ◽  
Srete Nikolovski

Abstract In this paper short-term planning algorithm for hybrid power system consist of different types of cascade hydropower plants (run-of-the river, pumped storage, conventional), thermal power plants (coal-fired power plants, combined cycle gas-fired power plants) and wind farms is presented. The optimization process provides a joint bid of the hybrid system, and thus making the operation schedule of hydro and thermal power plants, the operation condition of pumped-storage hydropower plants with the aim of maximizing profits on day ahead market, according to expected hourly electricity prices, the expected local water inflow in certain hydropower plants, and the expected production of electrical energy from the wind farm, taking into account previously contracted bilateral agreement for electricity generation. Optimization process is formulated as hourly-discretized mixed integer linear optimization problem. Optimization model is applied on the case study in order to show general features of the developed model.


2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Sandeep Gupta ◽  
Ramesh Kumar Tripathi

A current source converter (CSC) based static synchronous compensator (STATCOM) is a shunt flexible AC transmission system (FACTS) device, which has a vital role as a stability support for small and large transient instability in an interconnected power network. This paper investigates the impact of a novel and robust pole-shifting controller for CSC-STATCOM to improve the transient stability of the multimachine power system. The proposed algorithm utilizes CSC based STATCOM to supply reactive power to the test system to maintain the transient stability in the event of severe contingency. Firstly, modeling and pole-shifting controller design for CSC based STATCOM are stated. After that, we show the impact of the proposed method in the multimachine power system with different disturbances. Here, applicability of the proposed scheme is demonstrated through simulation in MATLAB and the simulation results show an improvement in the transient stability of multimachine power system with CSC-STATCOM. Also clearly shown, the robustness and effectiveness of CSC-STATCOM are better rather than other shunt FACTS devices (SVC and VSC-STATCOM) by comparing the results in this paper.


2013 ◽  
Vol 284-287 ◽  
pp. 1087-1093 ◽  
Author(s):  
Ya Chin Chang ◽  
Rung Fang Chang

As electricity demands and power transactions continuously increase, it becomes vulnerable to voltage instability for power systems, generally incurred by over-utilized facilities or any contingency. The transmission system loading margin (LM) enhancement problem with Static Synchronous Compensator (STATCOM) installation can be formulated as a mixed discrete-continuous nonlinear optimization problem (MDCP); due to the complexity of the MDCP, the computing burden might be very heavy. In the paper, the proposed ordinal optimization (OO) based STATCOM installation method is applied to the MDCP to solve for good enough solutions rather than the best solution, so as to largely reduce the computation burden. In the method, the crude method is first used to solve the MDCP and, based on OO theory, the exact method is then used to determine the good enough solutions. Finally, the good enough solution, as uses the fewest STATCOM device units for installation and makes the power system able to provide the required LM, is recommended for network reinforcement.


2021 ◽  
Vol 24 (4) ◽  
pp. 109-115
Author(s):  
Vyacheslav Valerievich Guryev ◽  
Vladimir Vyacheslavovich Kuvshinov ◽  
Boris Anatolevich Yakimovich

The Crimean Peninsula is the flagship of the development of renewable energy, as it is not only an actively developing region, but also a resort center. The energy complex of the Crimean Peninsula in recent years has increased due to the construction of new power plants (Balaklava TPP and Tavricheskaya TPP) with a total capacity of 940 MW, as well as the construction of new 220 and 330 kV transmission lines, which ensured that the peninsula’s power supply deficit was covered. A review of the regional development and use of renewable energy sources is carried out. Based on the data obtained, an analysis is made of the problems and prospects for the development of renewable energy in the region. The development of renewable energy for the Crimean Peninsula plays an important role in order to achieve environmental safety and develop the economic potential of the region. The paper substantiates the priority use of renewable energy in the region, as well as the solution of emerging problems with an increase in the share of renewable energy in the total generation. The appearance of excess electricity in the power system and the possibility of balancing the generated power of renewable energy and thermal power plants, while reducing the cost of electricity. Investment attractiveness and active population growth in the region leads to an increase in generating capacity and an increase in the maneuverability of the energy system with a significant impact of RES. The efficiency of renewable energy in the energy system, the world experience in managing renewable energy generation, the actual impact of renewable energy on the energy system in conditions of electricity shortage, and forecast work schedules of the SES wind farm provided by the electric power industry entities in the assigned way are taken into account when forming the dispatch schedule and are accepted at the request of the subject. The available experience of existing SES in the power system of the Republic of Crimea and the city of Sevastopol requires additional research, including through field testing of generating equipment. Further full-scale tests should be carried out under the conditions of a real electric power mode of the power system, which requires the introduction of modern information technologies that ensure the exchange of technological information and the implementation of appropriate control actions. The work is underway to create a regulatory framework for the control of renewable energy source operation.


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