scholarly journals On the possibility of participation of npps with vverin emergency frequency regulation in power system

2019 ◽  
Vol 21 (3) ◽  
pp. 99-108
Author(s):  
V. A. Khrustalev ◽  
M. V. Garievskii ◽  
I. A. Rostuntsova ◽  
A. V. Portyankin
Keyword(s):  
Power Systems ◽  
Power System ◽  
Nuclear Power ◽  
Power Plants ◽  
Frequency Control ◽  
Reactor Core ◽  
Operating Conditions ◽  
Frequency Regulation ◽  
Primary Control ◽  
Main Circulation

The purpose of the article is to study the possibility and feasibility of participation of nuclear power plants (NPPs) with VVER in emergency frequency control in power systems with a high proportion of nuclear power units and, at the same time, of reducing the power consumption for the own needs of the main circulation pumps during modes with power below nominal. To solve these problems, it was proposed to increase the achievable speeds of power gain (load increase) due to the installation of frequency controlled drives of the MCP. Large system frequency variations (caused by large imbalances between generation and demand) may jeopardize electrical equipment, in terms of maintaining stable and reliable operating conditions. For NPPs, the task of preventing or localizing accidents is even more important than for TPPs, since in case of major system accidents, it is possible to completely stop external power supply of the NPPs own needs. Thus, besides the requirements for the primary control of the frequency of NPPs with VVER, today we need more stringent requirements for their emergency acceleration and mobility. The operation of NPPs with long-term non-recoverable active power shortage causes a decrease in the speed of the main circulation pumps of NPPs with VVER and a decrease in the coolant flow rate. It is shown that the installation of variable frequency drives of the MCPs at NPP with VVER is appropriate not only to save energy consumption for their drive in partial modes, but also to increase the power of NPP above the nominal (without reducing the reserve before the heat exchange crisis in the reactor core) for the elimination of system accidents, and thus to improve the safety of the NPPs included in the power system.

scholarly journals Designing a GA-Based Robust Controller For Load Frequency Control (LFC)

2018 ◽  
Vol 8 (2) ◽  
pp. 2633-2639 ◽  
Author(s):  
K. Soleimani ◽  
J. Mazloum
Keyword(s):  
Power Systems ◽  
Power System ◽  
Power Plants ◽  
Frequency Control ◽  
Load Frequency Control ◽  
System Stability ◽  
Robust Controller ◽  
Power Flux ◽  
Pi Controllers ◽  
Multiple Units

Power systems include multiple units linked together to produce constantly moving electric power flux. Stability is very important in power systems, so controller systems should be implemented in power plants to ensure power system stability either in normal conditions or after the events of unwanted inputs and disorder. Frequency and active power control are more important regarding stability. Our effort focused on designing and implementing robust PID and PI controllers based on genetic algorithm by changing the reference of generating units for faster damping of frequency oscillations. Implementation results are examined on two-area power system in the ideally state and in the case of parameter deviation. According to the results, the proposed controllers are resistant to deviation of power system parameters and governor uncertainties.

scholarly journals Impact of Combined Demand-Response and Wind Power Plant Participation in Frequency Control for Multi-Area Power Systems

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1687 ◽  
Author(s):  
Irene Muñoz-Benavente ◽  
Anca D. Hansen ◽  
Emilio Gómez-Lázaro ◽  
Tania García-Sánchez ◽  
Ana Fernández-Guillamón ◽  
...  
Keyword(s):  
Power Plant ◽  
Power Systems ◽  
Wind Power ◽  
Demand Response ◽  
Power Plants ◽  
Frequency Control ◽  
Frequency Regulation ◽  
Wind Power Plant ◽  
Total System ◽  
Interconnected Power Systems

An alternative approach for combined frequency control in multi-area power systems with significant wind power plant integration is described and discussed in detail. Demand response is considered as a decentralized and distributed resource by incorporating innovative frequency-sensitive load controllers into certain thermostatically controlled loads. Wind power plants comprising variable speed wind turbines include an auxiliary frequency control loop contributing to increase total system inertia in a combined manner, which further improves the system frequency performance. Results for interconnected power systems show how the proposed control strategy substantially improves frequency stability and decreases peak frequency excursion (nadir) values. The total need for frequency regulation reserves is reduced as well. Moreover, the requirements to exchange power in multi-area scenarios are significantly decreased. Extensive simulations under power imbalance conditions for interconnected power systems are also presented in the paper.

scholarly journals TECHNICAL AND ECONOMIC ASPECTS OF DECARBONISATION PROSPECTS ASSESSING OF THE INTERCONNECTED POWER SYSTEM OF UKRAINE

2021 ◽  
Vol 2021 (5) ◽  
pp. 55-62
Author(s):  
B.I. Basok ◽  
◽  
O.F. Butkevych ◽  
S.V. Dubovskyi ◽  
◽  
...  
Keyword(s):  
Power Systems ◽  
Power System ◽  
Nuclear Power ◽  
Power Plants ◽  
System Capacity ◽  
Operational Conditions ◽  
Interconnected Power System ◽  
Net Zero ◽  
Installed Capacity ◽  
The Mathematical Model

Shot analysis of power systems decarbonisation problem to ensure a net-zero greenhouse gas emissions is given. The mathematical model of the power system capacity balancing, generating capacities of which are renewables and nuclear power plants (NPP) is proposed. For capacity balancing storage power plants (SPP) with specified efficiency indicators are used. By using the indicators of the operational conditions of the IPS of Ukraine in 2019 and mathematical modeling for various options of the NPP installed capacity in the decarbonised IPS of Ukraine, the needs in the renewables installed capacity and in the capacity and energy of various types of the SPP were estimated. References 10, figures 4, tables 2.

scholarly journals Analysis of the Implementation of the Primary and/or Inertial Frequency Control in Variable Speed Wind Turbines in an Isolated Power System with High Renewable Penetration. Case Study: El Hierro Power System

Electronics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 901 ◽  
Author(s):  
Guillermo Martínez-Lucas ◽  
José Ignacio Sarasúa ◽  
Juan Ignacio Pérez-Díaz ◽  
Sergio Martínez ◽  
Danny Ochoa
Keyword(s):  
Wind Speed ◽  
Power Systems ◽  
Power System ◽  
Wind Turbines ◽  
Wind Farm ◽  
Frequency Control ◽  
Frequency Regulation ◽  
Variable Speed ◽  
El Hierro

With high levels of wind energy penetration, the frequency response of isolated power systems is more likely to be affected in the event of a sudden frequency disturbance or fluctuating wind conditions. In order to minimize excessive frequency deviations, several techniques and control strategies involving Variable Speed Wind Turbines (VSWTs) have been investigated in isolated power systems. In this paper, the main benefits and disadvantages of introducing VSWTs—both their inertial contribution and primary frequency regulation—in an exclusively renewable isolated power system have been analyzed. Special attention has been paid to the influence of the delays of control signals in the wind farm when VSWTs provide primary regulation as well as to the wind power reserve value which is needed. To achieve this objective, a methodology has been proposed and applied to a case study: El Hierro power system. A mathematical dynamic model of the isolated power system, including exclusively renewable technologies, has been described. Representative generation schedules and wind speed signals have been fixed according to the observed system. Finally, in order to obtain conclusions, realistic system events such as fluctuations in wind speed and the outage of the generation unit with the higher assigned power in the power system have been simulated.

scholarly journals Simultaneous Inertia Contribution and Optimal Grid Utilization with Wind Turbines

2019 ◽  
Author(s):  
Clemens Jauch ◽  
Arne Gloe
Keyword(s):  
Power Systems ◽  
Power System ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Power Plants ◽  
Frequency Control ◽  
Negative Consequences ◽  
Realistic Case ◽  
Continuous Feed

This paper presents findings of a study on continuous feed-in management and continuous synthetic inertia contribution with wind turbines. A realistic case study, based on real measurements, is outlined. A wind turbine feeds into a weak feeder, such that its power has to be adapted to the permissible loading of this feeder. At the same time the wind turbine is to provide inertia to the grid by applying the previously published variable inertia constant controller. It is discussed that optimal grid utilisation and simultaneous inertia contribution are mandatory for the frequency control in power systems that are heavily penetrated with renewable energies. The study shows that continuous feed-in management can be combined well with continuous inertia provision. There are hardly any negative consequences for the wind turbine. The benefits for the grid are convincing, both in terms of increased system utilisation and in terms of provided inertia. It is concluded that wind turbines can enhance angular stability in a power system to a larger extent than conventional power plants.

scholarly journals Participation of Ukrainian NPPs in Regulating Frequency and Power in the United Energy System: Problem Analysis and Solutions

2020 ◽  
pp. 50-56
Author(s):  
V. Goldrin ◽  
I. Chervonenko ◽  
V. Zbinskiy ◽  
R. Brodich ◽  
O. Slonevskiy
Keyword(s):  
Control System ◽  
Power System ◽  
Power Unit ◽  
Nuclear Power ◽  
Power Plants ◽  
Energy System ◽  
Reactor Power ◽  
Frequency Regulation ◽  
Parallel Operation ◽  
Primary Frequency

The issue related to the participation of Ukrainian nuclear power plants in regulating frequency and power in the united energy system of Ukraine is considered in the paper. The dependence of frequency changes in the grid on the imbalance between generation and consumption of active power is presented. This can violate conditions of parallel operation of generators. Three levels of the frequency control system in the power system using backup capacities are examined. The issues of participation of nuclear power units in regulating frequency and power are studied. It is shown that the main factors limiting such participation are the characteristics of fuel assemblies. These characteristics govern the change in reactor power in a narrow range. An obstacle is also the mismatch of the characteristics of the equipment of power units for participation in regulating power system frequency. The complexity of regulating the electric power of a WWER nuclear power unit is under consideration, which is implemented by coordinated regulation of the reactor power and generator power. The regulatory requirements for the characteristics of the primary frequency regulation by nuclear power units is carried out. The possibility of their participation in the normalized primary frequency regulation are analyzed. The paper considers the concept of the National Nuclear Energy Generating Company “Energoatom” for the modernization of systems and equipment of WWER-1000 power units, which provides bringing the characteristics of power units in line with standards. The methodology for preliminary testing of the readiness of Zaporizhzhya NPP Unit 1 (“pilot” power unit) to participate in such regulation is described. The methodology involves testing at two power levels at the beginning and in the end of the fuel campaign. A signal is used to simulate a frequency deviation that is input via a separate train of the control system. The tasks, conditions and criteria for the success of the tests are described. Based on the test results, conclusions will be drawn about the possibility of the safe participation of WWER-1000 power units in the normalized frequency regulation in the united energy system of Ukraine and the necessary measures to modernize the equipment.

ANN-Based Self-Tuning Frequency Control Design for an Isolated Microgrid

2013 ◽  
pp. 357-385 ◽  
Author(s):  
H. Bevrani ◽  
F. Habibi ◽  
S. Shokoohi
Keyword(s):  
Power Systems ◽  
Frequency Control ◽  
Renewable Energy Sources ◽  
Electrical Energy ◽  
Operating Conditions ◽  
Frequency Regulation ◽  
Fast Development ◽  
Tuning Frequency ◽  
Optimal Approach ◽  
Intelligent Methods

The increasing need for electrical energy, limited fossil fuel reserves, and the increasing concerns with environmental issues call for fast development in the area of distributed generations (DGs) and renewable energy sources (RESs). A Microgrid (MG) as one of the newest concepts in the power systems consists of several DGs and RESs that provides electrical and heat power for local loads. Increasing in number of MGs and nonlinearity/complexity due to entry of MGs to the power systems, classical and nonflexible control structures may not represent desirable performance over a wide range of operating conditions. Therefore, more flexible and intelligent optimal approaches are needed. Following the advent of optimization/intelligent methods, such as artificial neural networks (ANNs), some new potentials and powerful solutions for MG control problems such as frequency control synthesis have arisen. The present chapter addresses an ANN-based optimal approach scheduling of the droop coefficients for the purpose of frequency regulation in the MGs.

Combined-Closed Gas Cycles for Terrestrial, Marine and Space Nuclear Power Systems

1992 ◽  
Author(s):  
Z. P. Tilliette
Keyword(s):  
Power Systems ◽  
Nuclear Power ◽  
Power Plants ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Efficiency Increase ◽  
Energy Conversion Systems ◽  
In Series ◽  
Space Nuclear Power ◽  
Direct Cycle

Higher temperature nuclear heat sources are becoming available and more efficient energy conversion systems can be proposed, namely Brayton-Rankine combined cycles which are presently very successful in the terrestrial fossil power plants market. A combined gas-steam cycle adaptation to the now being developed high temperature gas-cooled reactor MHTGR is presented. In order to avoid serious problems associated with the direct cycle, the concept features a He/He heat exchanger and a steam generator heated in series. Consequences are a significant plant efficiency increase, a sufficiently low reactor inlet temperature, attractive operating conditions and a possible reduction of the reactor water ingress hazard. Similar, judiciously simplified arrangements could be contemplated for possible future efficient marine nuclear power plants. Cycle combinations could also offer new, suitable approaches of space power systems, particularly for Lunar or Martian bases. A bottoming gas cycle could be a dramatic booster of a topping static thermionic converter, provided that a significantly larger radiator area be acceptable. Combined Brayton-Rankine cycles are also possible candidates for Moon or Mars surface power systems. As a consequence, should a gas-cooled reactor be used as the heat source in a direct cycle arrangement, its design could be drastically simplified.

IAEA Guidance on Enhancing the Safety of Electrical Power Systems

2016 ◽  
Author(s):  
Alexander Duchac ◽  
Magnus Knutsson
Keyword(s):  
Power Systems ◽  
Power System ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Electrical Power ◽  
Operating Experience ◽  
Electrical Power Systems ◽  
Open Phase ◽  
Phase Condition

An open phase condition is a known phenomenon in the power industry and is now recognized to have adverse impact on the electrical power systems in several nuclear power plants. An open phase condition may result in challenging plant safety. Operating experience in different countries has shown that the currently installed instrumentation and protective schemes have not been adequate to detect this condition and take appropriate action. An open phase condition, if not detected and disconnected in a timely manner, represents design vulnerability for many nuclear power plants. It may lead to a condition where neither the offsite power system nor the onsite power system is able to support the safety functions, and could propagate to station blackout. The design of electrical power systems needs to be evaluated systematically and improved, where necessary, to minimize the probability of losing electric power from any of the remaining supplies as a result of single or double open phase conditions. The improved design should be coordinated with existing measures to ensure that the electrical power system is able to support the safety functions after the open phase condition is detected and disconnected. In this regard, the IAEA has developed a safety publication dealing with design vulnerability of open phase conditions. This paper summarizes the contents of the report, the rationale and criteria to enhance the safety of nuclear power plants by providing technical guidance to address an open phase condition vulnerability in electrical systems used to start up, operate, maintain and shutdown the nuclear power plant.

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