Generation Rate Constraint Nonlinearity Research Articles

LFC performance advancement of two-area RES penetrated multi-source power system utilizing CES and a new CFOTID controller

This study addresses the challenges of load fluctuations and the assimilation of renewable energy sources (RES) causing undesirable frequency deviations. To avoid widespread deviations in frequency, an intelligent, competent and robust load frequency control (LFC) scheme and energy storage system are obligatory for disturbance rejection in RES penetrated realistic interconnected multi-source power system (IMSPS). Hence, a new cascade fractional order tilt integral derivative (CFOTID) controller is suggested with capacitive energy storage (CES) for a pragmatic RES based thermal-hydro-gas IMSPS having governor dead-band and generation rate constraint nonlinearities. The salp swarm algorithm (SSA) is utilized successfully for fine-tuning of the controller parameters. Scrutiny of the outcome results reveals the sovereignty of the CFOTID controller over several existing well proven controllers and SSA-based FOTID. It is observed that power generation due to CES further advance the system results in terms of minimized overshoot, undershoot, and settling time. Lastly, a sensitivity analysis is conducted to confirm the robustness of the controller.

Novel chaos game optimization tuned-fractional-order PID fractional-order PI controller for load\u2013frequency control of interconnected power systems

In this work, chaos game optimization (CGO), a robust optimization approach, is employed for efficient design of a novel cascade controller for four test systems with interconnected power systems (IPSs) to tackle load–frequency control (LFC) difficulties. The CGO method is based on chaos theory principles, in which the structure of fractals is seen via the chaotic game principle and the fractals’ self-similarity characteristics are considered. CGO is applied in LFC studies as a novel application, which reveals further research gaps to be filled. For practical implementation, it is also highly desirable to keep the controller structure simple. Accordingly, in this paper, a CGO-based controller of fractional-order (FO) proportional–integral–derivative–FO proportional–integral (FOPID–FOPI) controller is proposed, and the integral time multiplied absolute error performance function is used. Initially, the proposed CGO-based FOPID–FOPI controller is tested with and without the nonlinearity of the governor dead band for a two-area two-source model of a non-reheat unit. This is a common test system in the literature. A two-area multi-unit system with reheater–hydro–gas in both areas is implemented. To further generalize the advantages of the proposed scheme, a model of a three-area hydrothermal IPS including generation rate constraint nonlinearity is employed. For each test system, comparisons with relevant existing studies are performed. These demonstrate the superiority of the proposed scheme in reducing settling time, and frequency and tie-line power deviations.

Grasshopper optimisation algorithm of multistage PDF + (1 + PI) controller for AGC with GDB and GRC nonlinearity of dispersed type power system

This article introduces Grasshopper Optimisation Algorithm (GOA)-based multistage Proportional Derivative filter type (PDF) with One plus Proportional Integral (1 + PI) controller for Automatic Generation control (AGC) in dispersed type three area power system. The control-area 1 consists of thermal, hydro and Wind units. Similarly, control-area 2 consists of thermal, hydro and Diesel units. Control-area 3 consists of thermal, hydro and Gas units. Nonlinearities like Governor dead-band, GRC (generation rate-constraint) and boiler dynamics are included for realistic representation. A comparative analysis is carried out by GOA with multistage PDF + (1 + PI) controller with classical PID/PI controller to justify the superiority of the proposed controller. The dominance characteristic of GOA with PDF + (1 + PI) controller structure is tested over Particle swarm optimisation (PSO) and Genetic algorithm (GA) optimisers with PDF + (1 + PI) controller. The robustness of the complete framework was justified by study and analysis of sensitivity by enhancing and decaying SLP and system elements in a band 50% from its minimal value. From the analysis, it is found that the GOA method with PDF + (1 + PI) controller is providing dominance characteristics performance with random load variations and system parameters of the various components of the power system.

Optimal AGC Design for a Hybrid Power System Using Hybrid Bacteria Foraging Optimization Algorithm

This paper proposes a hybrid optimization algorithm developed through the novel combination of particle swarm optimization (PSO) oriented bacteria foraging optimization algorithm (BFOA) for finest tuning of proportional integral derivative (PID) controllers for load frequency control problem of hybrid power system comprising of photovoltaic (PV) system and thermal generators. In order to prevent the solution from sub-optimal condition and to accelerate the convergence time of the problem the PSO is merged with BFOA to solve the LFC problem of the hybrid system. To check the power of the proposed strategy initially the hybrid system is evaluated for step load change and the results are compared with some powerful optimization algorithms such as BFOA, PSO, and flower pollination algorithm (FPA) based PID in terms of computed gains and achieved value of error. The results obtained show the cost and control efficacy of the proposed design. The study is extended to investigate the performance of proposed design with dead-band of governor and generation rate constraint non-linearity. Finally, the robustness of the proposed design is evaluated for random load change, sinusoidal load change and for extensive parametric variations from the typical plant values and the application results are presented.

Optimal design of fuzzy PID controller for deregulated LFC of multi-area power system via mine blast algorithm

This paper presents a novel optimal fuzzy proportional–integral–derivative (fuzzy PID) controller for load frequency control (LFC) designed by a proposed approach of mine blast algorithm (MBA) for multi-interconnected areas. The system includes reheat thermal connected power systems with the effect of the governor dead zone and turbine generation rate constraint nonlinearity. The proposed approach is used to determine the optimal parameters of the fuzzy PID controller to minimize the integral time absolute error. The proposed controller is inserted in multi-interconnected power systems which are built in Simulink/MATLAB library; triangular membership function is used for fuzzy PID controller. Additionally, the optimum adjustment of the fuzzy PID controller parameters under contracted scenario for large step demands and disturbances is investigated by MBA. The obtained results are compared to those obtained via antlion optimizer, artificial bee colony, hybrid differential evolution particle swarm optimization and hybrid PSO pattern search algorithm. The obtained results confirmed the superiority of the proposed MBA in designing the fuzzy PID-LFC as it provides less error with best statistical parameters compared to the others.

AGC of Multi-Area Hydro-Thermal Power Systems With GRC Non-Linearity and Classical Controller

In this article, the optimal gain value of classical controller gain values is obtained by using different performance indices in Automatic Generation Control. These are interconnected by the three areas of a hydro-thermal power system. The thermal and hydro areas are incorporated with a reheat turbine and a mechanical governor, respectively. The current article was created to select a suitable technique for the tuning of controller gain, when 1% of a step load is given to the thermal area (Area 1). The performance of several controllers, such as Integral (I), Proportional-Integral (PI), and Integral-Derivative (ID) were evaluated and were compared to the cases of with and without Generation Rate Constraint (GRC) non-linearity. The classical controller gain value optimization was performed using the Integral Time Square Error (ITSE), Integral Square Error (ISE) and Integral Time Absolute Error (ITAE) performance indices. The minimum optimal value of controller gain normally offers better dynamic response. The obtained results established that the optimization based on the ITAE-PI controller always guarantees superior dynamic performances compared to other indices and controllers.

Frequency stabilization of multi-area multi-source interconnected power system using TCSC and SMES mechanism

The present aspect studies automatic generation control (AGC) of a multi-area multi-source test system with the effects of thyristor controlled series compensation (TCSC) and superconducting magnetic energy storage (SMES) units. The studied test system is a three-area power system model having thermal–thermal unit in area-1, thermal-hydro unit in area-2 and thermal-gas unit in area-3. The same is imposed by appropriate time delay, governor deadband, generation rate constraint nonlinearities. A nature-inspired optimization technique called moth-flame optimization algorithm is implemented for solving the constrained optimization parameters. The step load perturbation (SLP) and random SLP are used for the dynamic performance analysis. The designed controller based dynamic responses are also studied with wide perturbation in parametric values through robustness analysis. Analysis reveals that the proposed control strategy, considering SMES and TCSC units, improves the dynamical performances of system significantly in terms of settling time and overshoot against parametric uncertainties against a wide range of area load demands and disturbances even in the presence of system nonlinearities.

Load frequency control of power systems with non‐linearities

Load frequency control (LFC) for power systems with governor deadband (GDB) and generation rate constraint (GRC) non-linearities is discussed in this study, with the objective to add anti-windup schemes for any designed LFC controller, so that the stability and performance of the existing LFC controller can be retained when there are non-linearities. Effects of GDB and GRC on the performance of LFC controllers are first analysed via describing function method. Anti-windup schemes are then proposed to compensate the GDB and GRC non-linearities. For GDB, the error between the realistic and the ideal outputs of the generator is added to the output of LFC controller for rejection, and for GRC, the error between the realistic and the ideal outputs of the turbine is fed back to the observer of the LFC controller for estimation and elimination. Simulation results show that the compensation schemes are effective in overcoming the adverse effects of GDB and GRC.

Automatic generation control of multi source power generation under deregulated environment

Abstract This paper presents a novel scheme for automatic generation control (AGC) of interconnected two area multi source power generation under deregulated environment. The conventional two-area AGC system is modified to take into account the effect of bilateral contracts on the dynamics. In the considered two area power system, each area contains two GENCOs; first GENCO is a reheat steam turbine with appropriate generation rate constraint nonlinearity and second GENCO is a gas turbine generation. The performances of integral (I), proportional-integral (PI), integral-derivative (ID) and proportional-integral-derivative (PID) are evaluated for the proposed AGC system in the deregulated environment. The gain of the controllers and speed regulation parameters are optimised using differential evolution (DE) algorithm. Differential evolution algorithm is used because of its convergence superiority and easy to implement. The performance of DE algorithm applied to the proposed problem is compared with that of Genetic Algorithm (GA) to establish its optimisation superiority of the former.

MOEA based Design of Decentralized Load-Frequency Controllers for Interconnected Power Systems with AC-DC Parallel Tie-lines and Considering Nonlinearities

A new approach to the design of decentralised controllers, using Multi-Objective Evolutionary Algorithm (MOEA), for loadfrequency control of interconnected power systems with AC-DC parallel tie-lines and considering Governor Dead Band and Generation Rate Constraint nonlinearities, is proposed in this paper. The HVDC link is used as system interconnection in parallel with AC tie-line to effectively damp the frequency oscillations of AC system. The proposed controller satisfies two main objectives, namely, minimum Integral Squared Error of the system output and maximum closed loop stability of the system. Simulation studies are conducted on a two area interconnected power system with AC-DC parallel tie lines and considering nonlinearities. Results indicate that the proposed controller gives good dynamic responses and can guarantee the stability of the overall system in the presence of system nonlinearities and parameter changes.

MOEA based design of decentralized controllers for LFC of interconnected power systems with nonlinearities, AC–DC parallel tie-lines and SMES units

A new design of Multi-Objective Evolutionary Algorithm based decentralized controllers for load–frequency control of interconnected power systems with Governor Dead Band and Generation Rate Constraint nonlinearities, AC–DC parallel tie-lines and Superconducting Magnetic Energy Storage (SMES) units, is proposed in this paper. The HVDC link is used as system interconnection in parallel with AC tie-line to effectively damp the frequency oscillations of AC system while the SMES unit provides bulk energy storage and release, thereby achieving combined benefits. The proposed controller satisfies two main objectives, namely, minimum Integral Squared Error of the system output and maximum closed-loop stability of the system. Simulation studies are conducted on a two area interconnected power system with nonlinearities, AC–DC tie-lines and SMES units. Results indicate that the proposed controller improves the transient responses and guarantees the closed-loop stability of the overall system even in the presence of system nonlinearities and with parameter changes.

Decentralized biased dual mode controllers for load frequency control of interconnected power systems considering GDB and GRC non-linearities

A new design of decentralized biased proportional and integral dual mode controllers for load frequency control of interconnected power systems considering governor deadband (GDB) and generation rate constraint (GRC) non-linearities is presented in this paper. Any optimum controller selected for load frequency control of interconnected power systems should not only stabilize the power system but also reduce the system frequency and tie line power oscillations and settling time of the output responses. Hence, a simple design of biased controllers with proportional and integral modes using an integral square error (ISE) criterion and maximum stability margin (MSM) criterion based on minimum settling time for interconnected power systems are discussed. These controllers are designed and implemented in a two area interconnected thermal power system with GDB and GRC non-linearities. The proposed controller is found to be simple in structure and easy for implementation. The closed loop system was simulated, and the frequency and tie line power deviations resulting from a step load disturbance are presented. Comparison of the performances of the proportional plus integral biased controller and the proposed proportional (P) and integral (I) biased dual mode controllers shows that the system performance is improved significantly with the proposed controllers. Further, it is also shown that the biased dual mode controllers are found to be less sensitive to changes in system parameters.