The earliest study designed for regulating the governor system was based on the PID controller. But at the results of the output are still found weaknesses, such as the occurrence of a long enough oscillation at the output before going to the steady state area . To overcome these problems, the governor control technique based on Fuzzy Logic Controller (FLC) was developed . This method can reduce oscillation, but with very slow response. Another effort that has been done is to combine fuzzy methods with conventional Proportional Integral (PI) controllers to provide an increase in system response . In the existence of fuzzy, PID parameters are made to be more able to adapt to changes in load. The following methods were Adaptive Fuzzy-PID  and Robust H∞ Control . However, the control techniques were only prepared for small change of load. From several studies above the main problem seen in governor-basedfrequency regulation is the slow response given by the governor system to return the frequency back to its original frequency when a load change occurs, especially for sudden significant changes. An alternative platform in MHPP frequencycontrol that has been developed intensively during the last decade is ElectronicLoadControl (ELC). The ELC consists of three- phase rectifier circuit, which on one hand is able to accelerate frequency recovery significantly, but can cause a fairly high harmonic level at the generator output . ELC is used to absorb power with large changes. The ELC circuit works by diverting current on the load bus to ballast load. The ELC circuit requires a control technique to determine the amount of current flowing into ballast load.
basis of the integral error criterion. A PID tuning method based on the two-degree-of-freedom internal model control for LFC of power systems is presented in , which the method is applicable to power systems with non-reheated, reheated, and hydro turbines. The impact of interline powerflowcontroller and redox flow batteries on an interconnected two-area multiple-unit thermal reheat power system in restructured environment is presented in . In , the design and analysis of a robust PID controller for a hydraulic turbine generator governor using a frequency response technique are presented. The analysis of automatic generation control (AGC) of a two-area interconnected hydrothermal power system to damp the system frequency and tie-power oscillations by controlling the phase angle of thyristor- controlled phase shifter (TCPS) in series with the tie-line has been investigated in , which gain settings of the integral controllers are optimized using integral squared error (ISE) technique by minimizing a quadratic performance index. A PID tuning technique using internal mode control for decen- tralized loadfrequencycontrol in deregulated environment has been investigated in .
Nigeria power system is faced usually with the problems of insufficient generation and transmission lines, hence resulting in the overloading and stressing the network beyond their thermal limit, because of the increasing load demand. The resultant effect is having the transmission lines voltages operating outside the allowable limit of + or - 6%, insufficient and inadequate powerflow, high line losses, and damping oscillation. In an attempt to solve these challenges, the federal government through Independent Power Producers (IPP) and National Independent Power Projects (NIPP) embarked on building more generating stations and additional transmission lines. The Implication of this attempt, is that the network soon will become complex and will require thorough control of basic parameters. Control parameters such as bus voltages, power flows (active and reactive), phase angles and line currents become very important. Conventionally, these controls were achieved using reactors, capacitor banks and tap changing transformers (phase shifters) to regulate power flows. Due to their slow response to system changes, powerelectronicbased devices became imminent because of their speedy and accurate response to controls. With the integratedpower project to solve some of these peculiar problems, government still face some challenges; such as delay in obtaining right of ways in building transmission lines and having generating stations located
Turbine governors are systems for the control and adjustment of the turbine power output and for evening out deviations between the power and the grid load as quickly as possible. Two main governors are used to automatically control the frequency of the generating unit). First, it could remain constant by action on the gate opening position to produce just the necessary power according to the connected\ load. Second, electronicload controllers (ELC) govern the frequency by adjusting the electrical load connected to the alternator. Therefore, they maintain a constant electrical load on the generator in spite of changing users' load. In this case, the turbine gate opening is kept in a specific position that guarantees a nominal mechanical power at the generator shaft. It permits to use turbine with no flow regulating devices. The former governor takes a long time to stabilize the output and it becomes insufficient in case of large load variations where the stability of the system could be completely lost. ELC is used in order to simplify the MHPP control. The stabilizing time is short even for large load variations.
The continuous growth in size and complexity of interconnected power systems, along with both area frequency and tie-line power interchange. The main purpose of loadfrequencycontrol (LFC) is to sustain frequency of the system under prescribed limits and check the fluctuations on tie-line loading in case of multi area power system. Past year Automatic generation control (AGC) system specifies an applicable way to hold a control over the frequency and tie line powerflow. Different methods have been suggested for LoadFrequencyControl. The best common technique which is commonly used around world since few years is based Proportional Integral (PI) controllers, but with exponentially increasing electricity market essential for more progressive control techniques arises for correct effective of large numbers of interconnected multi area generating units. The control of loadfrequency and the operational aspect of automatic generation control for a multi area hybrid interconnected power system In the large interconnected power system the risk of network failure is increased many times as the system frequency is related to Active power. The two predictable controllers are based on the theories of PI and artificial neural network which is being tested on the three area interconnected hybrid power system which embraces thermal powerplant with and without re-heater and hydro powerplant with different loading. As it is apparent that frequencycontrol is laggard control when paralleled against voltage control so it is necessary to reduce the transient time in loadfrequencycontrol to boost the overall power system performance. Both the proposed controller is discussed in details with respect to their working and implementation in interconnected power system network completely replacing the present day PI controller. An iterative linear estimate built matrix algorithm is framed to linearize the system. Modern control technique based on network Fuzzy Logic basedController (FLC),Artificial Neural Network (ANN), and genetic algorithm crafted are assessed for LFC problem. Yet bountiful exertion have been made for optimizing predictable LFC but very less exertion for designing intelligent controller for multi area power system.
Abstract—Successful operation of an interconnected power system requires the matching of total generation with total demand and associated system losses. With time as the operating point of a power system changes, and hence, these systems may experience deviations in nominal system frequency and scheduled power exchanges to other areas, which may yield undesirable effects. The two variables are considered for the evaluation of the system performances namely, frequency and tie-line power exchanges. In this two-area symmetrical thermal reheat system with stiff and elastic tie lines are considered for simulation controllers using proportional and integral are designed and the simulated results are analyzed for better performance.
In this paper, two-area power system is considered as a test system, which consists of reheat turbine type thermal station in each area. The system model under consideration is shown in Fig. 2. The LFC has two control loops. The primary control loop is used to control the frequency by using self-regulating feature of the governor. But, frequency error is not completely eliminated & the supplementary control loop is used to eliminate the frequency error completely with the help of conventional integral control action. The main aim of the supplementary control loop is to restore balance between each control area load & generation after a load disturbanceso that the system frequency & the tie-line power flows are maintained at their nominal values.Thus, in this paper main task is to minimize the system frequency deviation f 1 in area 1, f 2 in area 2 & deviation in the tie-line powerflow P tie between the two areas under the load disturbances Pd 1 & Pd 2 in the two areas. This can be achieving by using integral control action.
conventional energy and towards to use renewable energy like hydropower system, solar cells and wind turbines as soon as possible. LoadFrequencyControl (LFC) problem is coming to be the main topics for mentioning schemes due to not corresponding between main power system inputs such as change load demand and change in speed turbine settings. This paper illustrates a self- tuning control of hydropower system that suggested and confirmed under Automatic Generation Control (AGC) in power scheme. The suggested power system involves one single area. The suggested self-tuning control system is employed in performing the automatic generation control for loadfrequencycontrol request and compared it with conventional control structure. The power system dynamic modeling has regularly built in several essential parameters which have a significant influence According to frequency limitation. The main problem with all controllers is an exaggerated reaction to minor errors, producing the system to oscillate. The output response results for hydropower system obviously proved the benefit of using maximum load demand by tuning PID controller. Whereas, tuning PID controller has got properly more rapid output response and minimal overshoot.
Static IP-address: With this setting, the possibility is given to assign a pre-defined IP- address to the Energy Valve, as well to assign the subnet mask and gateway to it. This method can be used, if the network administrator is managing the network addresses without a DHCP server.
The main purpose of the AGC loadfrequencycontrol is to not only maintain the frequency of system constant as well as zero steady state error and tie line powerflow in desired direction. This paper is aim to study the three area interconnected power system for loadfrequency fluctuation and developing a controllerbased on fuzzy logic to minimise these deviation. The interconnected system three area will have aamalgamation of hydro and thermal basedpower station.
In its general form the Interline PowerFlowController employs a number of dc to ac inverters providing each series compensation for a different line. In other words, the IPFC comprises a number of Static Synchronous Series Compensators. However, within the general concept of the IPFC, the compensating inverters are linked together at their dc terminals, as illustrated in Fig. 2. With this scheme, in addition to providing series reactive compensation, any inverter can be controlled to supply real power to the common dc link from its own transmission line. Thus, an overall surplus power can be made available from the underutilized lines which then can be used by other lines for real power compensation. In this way, some of the inverters, compensating overloaded lines or lines with a heavy burden of reactive powerflow, can be equipped with full two-dimensional, reactive and real powercontrol capability, similar to that offered by the UPFC. Evidently, this arrangement mandates the rigorous maintenance of the overall power balance at the common dc terminal by appropriate control action, using the general principle that the under loaded lines are to provide help, in the form of appropriate real power transfer, for the overloaded lines.
However, higher cost, long building cycle and low reliability still limit its widespread application because the high power converter design is still customized and non-standard. The distributed powerflowcontroller (DPFC) module based on ETO Light converter with the rating of 1 - 2 MVA single phase configuration is proposed in this dissertation. It has lower cost and higher reliability compared with existing high power converter designs. The standard modular design of DPFC enables easy installation and maintenance. Transformerless connection is enabled by high voltage/current capability and the controlpower self-generation function of ETO Light converter . The medium rating (1-2MVA) is very suitable for distributed applications. The fault tolerant capability made possible by redundancy can be achieved to enhance reliability and availability . The modular design of megawatt DPFC raises a good opportunity of high power converter applications in the power transmission system. Unlike the traditional three-phase power converter-based SSSC, the DPFC applies distributed per-phase control, which means the DPFC module only measures the current and voltage information in one phase transmission line and controls the active power through this single-phase line. This DPFC concept can also be applied to distribution systems and even in Demands Side management (DSM) .
Understanding of the frequency dynamics of power systems is essential for several issues including frequencycontrol design and estimation of the system inertia through measurements. Consider a power system with several conventional synchronous generators. If this power system is subjected to a disturbance such as a sudden outage of a generator, then dynamical changes in the system start instantaneously. These dynamics are mainly caused by the instantaneous power imbalance between the instantaneous generation and consumption of electric power. Consequently, the remaining synchronous generators are subjected to acceleration and deceleration effects. Due to the strong connection between the mechanical and electrical frequency, the changes in the rotor speed results in changes in the electrical frequency. Eventually, the power balance and the frequency are restored in the system has sufficient capacity to compensate the lost generation. This control action is called primary Automatic LoadFrequencyControl (ALFC). In this direction, the load-frequencycontrol (LFC) is one of important control problems in concerning the integration of wind power turbine in a multi-area power system [2, 8, 18, 20, 21].The increasing need for electrical energy in the twenty-first century, as well as limited fossil fuel reserves, very high transportation and fuel cost and the increasing concerns with environmental issues for the reduction of carbon dioxide (CO2) and other greenhouse gasses, causes fast development in the area of renewable energy sources (RESs). One of the adaptive and nonlinear intelligent control techniques that can be effectively applicable in the frequencycontrol design is reinforcement
Interconnected power systems consist of many control lines. The block scheme of an area power system is shown in Fig. 1. All blocks are generally nonlinear, time-variant minimum phase systems . In each control area, the generators are assumed to form a coherent group. Loads changing at operating point affect both frequencies in all areas and tie-line powerflow between the areas . As known that power ave parametric uncertainties and they must have small oscillations in the magnitude of transient frequency. Their speed control must be taken care of as quickly as possible . The load-frequencycontrol generally is accomplished by two different actions in interconnected three-area power systems: (a) the primary speed control and (b) supplementary or secondary speed control actions. The former performs the initial vulgar readjustment of the frequency by which generators in the control area a load variation and share it in proportion to their capacities. This process typically takes place 20 s. The latter takes over the fine adjustment of the frequency by resetting the frequency error to zero through an integral action. The hip between the speed and load can be adjusted by changing a load reference set point input. In practice, the adjustment of the load reference set point is accomplished by operating the speed changer motor. The output of each unit at a given system cy can be varied only by changing its load reference, which in effect moves the speed-droop characteristic up and down. This control is considerably slower and goes into action only when
parameters with tuning to show satisfactory performance and results. In this Direct Synthesis(DS) approach, the design is based on a desired closed loop transfer function for a particular second-order-plus- dead-time(SOPDT) system. From such a Direct Synthesis(DS) controller, PID controller design with various methods. Generally Direct Synthesis technique is a advanced technique to reduce higher order system to low order system(SOPDT) and system is less complex and all parameters(% overshoot, settling time, rise time and steady state error) of the system is less than Ziegler-Nichols, Tyreus-Luben tuned controller and Internal Model Controlbased PID Control. Many advanced control strategies developed and implemented in loadfrequencycontrol and automatic generation control of single area Power system, double and multi area Power system[15-18] e.g. Robust PID controller design method base on the maximum peak resonance specification may be given in[19- 20].The rest of the paper is organize as follows: The transfer function model of Non-Reheated Turbine Power system with no Droop characteristic was presented in Section 2, A PID controllers being designed for a first, second and higher order system with transfer function in Section 3, Different types of technique use to design a PID controller in Section 4, Simulation results and discussions are given in Section 5 and finally the paper is concluded in the Section 6.
Abstract- Now a days the issue on Loadfrequencycontrol in interconnected power system different area how maintain. The main objective of Automatic Generation Control (AGC) is to balance the total system generation against system load losses so that the desired frequency and power interchange with neighboring systems is maintained. Any mismatch between generation and demand causes the system frequency to deviate from its nominal value. Thus high frequency deviation may lead to system collapse. This necessitates a very fast and accurate controller to maintain the nominal system frequency. This paper deals with loadfrequencycontrol of an interconnected two area hydro-hydro system. The system is incorporated with conventional proportional-integral (PI) and fuzzy logic controller (FLC). We are assuming that all areas in a system operate at the same frequency because the traditional approach for interconnection turned out to be unsuccessful for hydro-hydro systems. Time domain simulation is used to study the performance, when a 0.5% step load disturbance is given in area of the system. Finally the simulation results of conventional PI controller is compared with fuzzy logic PI controller and proved that FLC yields better control performance.
A real three-area interconnected power system existing in the gulf region is considered as a simulation example to investigate the effectiveness of the proposed BFOAlogrithm.The three area power system is shown in fig.3.The system parameters are given table 1. It is assumed that no fuzzy control rules are available for the proposed BFOA.Comparisons between simulation results of the proposed BFOA and those of a PID classical controller, designed using Ziegler-Nichols method, and a type-2 fuzzy decentralized LFC(Type-2 Fuzzy) ,DIAFLC are carried out in the presence of GRC and GDB. The parameters of the DIAFLC and the PID controller are tabulated in Table II and the “If-then” rules for the Type-2 fuzzy controller are given in Table III.
Values by using Particle Swarm Optimization Technique. Three types of Fuzzy Controllers are proposed and analyzed. The similar controllers are proposed for the two identical areas for a Two area LoadFrequencyControl over different range of operating conditions. The simulation study shows that the stability of the system is improved with less overshoot/undershoot with the FPD controllers with minimum oscillations and less settling time than FPI controller.FPID controller efficiently reduces the overshoot/undershoot by damping the oscillations negligibly. References:
regarding the load-frequencycontrol of single and multi area power systems . The main purpose of loadfrequency controllers is to ensure the stable and reliable operation of power systems. Loadfrequencycontrol in power systems introduces as one of the most important items in order to supply reliable electric power with good quality some of the proposed methods in literature deal with system stability using fixed local plant models ignoring the changes on some system parameters. Nowadays, with the development in digital technology, it has become possible to develop and implement new controllers based on modern and more sophisticated synthesis techniques. Indeed, controllers based on robust optimal control, adaptive control, artificial intelligence (Fuzzy logic, neural networks, and genetic algorithms) are being developed. This paper PID controller has been designed for higher order system using Ziegler-Nichols frequency response method and its Performance has been observed with plant data. The most popular tuning technique is the Ziegler-Nichols method. However, besides being suitable only for system with monotonic step response, the compensated system whose controllers are tuned in accordance with the Ziegler-Nichols method have generally a step response with a high- percent overshoot. Ziegler and Nichols proposed the manual tuning of PID controller. The Ziegler Nichols tuned controller parameters are fine tuned to get satisfactory performance.
In 2018, Kanti et al.  have aimed for designing a higher order sliding mode control for the issue of LFC by decentralised control model. Then the developed controller ensures the alterations in frequency in total areas due to the coverage of load disturbance to zero in finite time. Finally, the outcomes were compared to the attained performances by ISMC as well as IHOSMC. Subsequently, the developed controller aids in attaining the finite time convergence of frequency change because of load disturbances were compared with the attained one by ISMC and IHOSMC. The controller performance was tested for the concerned plant with non-linearities exists in power system including conditions of generation rate and governor deadband. Moreover, the validation of developed controller over random load disturbances was done and proven the superiority of proposed system. In 2017, Yang et al.  have developed a novel model for the issue of stability, one-area and multi- area LFC model along time delays. They have derived the new stability criteria along delay dependency with respect to inequalities of linear matrix for LFC systems through the augmented Lyapunov–Krasovski functional. The design of LFC takes the interval time-deviating communication delays, and they have also modeled the load disturbance as the non-linear function (normbounded). Further, the examination has suggested a novel class of inequality by the intermediate auxiliary functions, and that could grant high tighter bounds. Finally, certain case studies have taken place for illustrating the efficiency of developed design model.