Availability Based Tariff Research Articles

Impact of ABT based control strategies on ALFC and AVR in DFIG-integrated interconnected power systems

To maintain a stable electricity supply in interconnected power grids, effective frequency and voltage regulation are required. Interconnected power systems use Automatic Load Frequency Control (ALFC) and Automatic Voltage Regulator (AVR) for this purpose. The integration of renewable sources, such as Doubly Fed Induction Generators (DFIGs), creates challenges for such control loops. This study investigates the impact of using various Frequency-Linked Pricing (FLP)-based operating strategies under Availability-Based Tariff (ABT) on combined ALFC and AVR in a two-area interconnected power system with DFIGs. FLP-based operating strategies under ABT react to frequency changes through price signals, which can act faster compared to traditional AGC methods that rely on communication between control centers. This quicker response helps maintain frequency and voltage during load disturbances. Most of the earlier research focused mostly on using only a single type of FLP-based operating strategy under ABT within the ALFC loop, neglecting the combined ALFC-AVR interaction. This work addresses this gap by evaluating three FLP-based operating strategies under ABT along with the traditional approach for their impact on frequency and voltage under step load disturbance. Simulation studies conducted in MATLAB 2022a demonstrate the effectiveness of the proposed strategies, providing valuable insights for improving frequency and voltage control in modern power systems. The investigation reveals that the strategy that considers the difference between the actual and reference values of the unscheduled interchange (UI) charge and the marginal cost of generation to produce the control command outperforms the other strategies and restores the frequency and voltage to their nominal values.

Frequency regulation in interconnected power system with DFIG participation under ABT-based various operating strategies

The implementation of various operating strategies based on the Availability Based Tariff (ABT) in a two-area interconnected power system with thermal and DFIGs in each area for frequency regulation is investigated in this paper. A suitable Generation Control Error (GCE) signal is needed to regulate frequency and tie-line power flow in an ABT-based operating strategy. This signal combines marginal generation cost and frequency-dependent unscheduled generation cost. A GCE signal generated in succession by three distinct operating strategies controls all thermal generators. To determine the best ABT-based operating strategy for the system under consideration, a simulation study is performed to compare and analyse the corresponding system responses. The operating strategy that utilises GCE, which is the difference between unscheduled interchange charges and marginal cost from their reference values, performed better than the other frequency regulation operating strategies. Furthermore, the simulation study compares traditional and identified ABT-based better control strategies.

Automated Generation Control of Multiple-Area Electrical System with an Availability-Based Tariff Pricing Scheme Regulated by Whale Optimized Fuzzy PID Controller

In this research, a whale-optimized fuzzy PID controller was developed to manage automatic generation control in multiple-area electrical energy systems with an availability-based tariff (ABT) pricing scheme. The objective of this work is to minimize the power production costs, area control errors (ACEs), and marginal costs of the multiple-area electrical energy system with real-time load and frequency variation conditions. The generation of power, deviation of power in the tie line, and deviation of frequency of the interconnected three-area electrical energy system, including the hydrothermal steam power plant and gas power plant, will be measured and analyzed rigorously. Based on the output from the whale optimization, the fuzzy PID controller regulates the deviation of power in the tie line and the deviation of frequency of the interconnected three-area electrical energy system. The reliability and suitability of the proposed optimization, i.e., whale-optimized fuzzy PID controller, are investigated against already presented methods such as particle swarm optimization and genetic algorithms.

ANFIS controller based frequency linked availability based tariff mechanism for a restructured power system

This paper proposes the frequency linked availability based tariff (ABT) mechanism along with ANFIS controller for extenuating the issues in load frequency control (LFC) for a four area deregulated/restructured power system. To scrutinize the effective performance of the proposed approach, the dynamic performance of the system is analyzed with single and bilateral contract considering the value of the marginal cost higher and lesser than the Unscheduled interchange (UI). For this analysis, UI rate chart from the Central Electricity Regulation Commission (CERC) is used. The simulation results confirm that the ANFIS controller performance is comparatively better than proportional controller in two different contract cases.

Automatic Generation Control (AGC) operation in a restructured power system under Availability Based Tariff (ABT) mechanism by considering peak hours and off-peak hours

Objectives: To simulate automatic generation control (AGC) operation in a deregulated power system under availability based tariff (ABT) mechanism to regulate grid frequency during peak and off-peak hours. Method: For the simulation, the two areas, an isolated power system with Area1, which has thermal - hydropower plants with two DISCOs, and Area2 having a thermal – thermal power plant with two DISCOs have been considered. DISCO participation matrix (DPM) has been used for the visualization of bilateral contract by distribution companies (DISCOs) in the restructured environment. An AGC operation of two area power system with 10% load variations during peak hour and off-peak hour has been presented for the 24 hours in graphical form. Findings: The deviations in the grid frequency and Unscheduled Interchange (UI) charges or deviation settlement mechanism (DSM) rates of ABT due to sudden load changes and renewable power found. The frequent AGC operation of generators against load variation to stabilize the grid frequency is increasing wear and tear losses which finally increases maintenance cost and sometimes tripping of generators. Also, in peak hours and off-peak hours the drastic change in UI charges found during AGC operation so, there is a need to regulate grid frequency from the load side using distributed energy sources. Novelty: In proposed work, at the distribution side, Electric vehicle has been considered to regulate grid frequency during peak and off-peak hours. Work has been justified by appropriate data and simulated results. Keywords: AGC; deregulation; peak hours; offpeak hours; ABT

Fuzzy inference based irrigation controller for agricultural demand side management

The efficient and sustainable irrigation mechanism results in reduced water loss and improved crop productivity. This paper presents a real-time fuzzy inference based automated irrigation controller implemented in LabVIEW, that utilizes the data logged from the sensor network and communicated using GSM/GPRS module. The proposed drip irrigation scheduler receives the data from soil moisture, humidity, air temperature and water level sensor, in order to decide the percentage valve opening. Recently the open channel system have transformed into pressurized pipe systems which utilizes large amount of energy for uniform distribution of water. In order to optimize the energy consumption utilized in irrigation, availability based tariff (ABT) is implemented. The time interval for which drip irrigation is regulated, is controlled by supply frequency to operate pumps in low tariff period. This technique is applicable for wide range of crops which are grown in Kharif and Rabi season. The field experimentation results shows that the cost of irrigation is reduced by 30% as the water and electricity is efficiently utilized. Water saving is 45% more as compared to flood irrigation mechanism. Cost benefit achieved for Sorghum crop cultivation by proposed fuzzy based irrigation technique is higher by Rs.598/acre than the profit realized by manual flood irrigation.

Automatic Generation Control of a Two Area Thermal-Thermal Deregulated Power System with HES and TCPS units for Unscheduled Interchange Price Signals

Automatic Generation Control (AGC) plot for two area inter-connected thermal to thermal Deregulated Power System (DPS) utilizing Unscheduled Interchange (UI) price signal, which has an effect on the power markets is proposed in the paper. Unscheduled Interchange price is one of the most important parts of Availability Based Tariff (ABT) which goes about as an optional control system for regulating the grid frequency. These UI price signals vacillate according to change in grid frequencies which can be open by the participants (generator or load) associated with the grid. The customary AGC system, however, attempts to carry the error of frequency to 0, yet it will be an ineffectual answer for taking an interest producing penalty deviations with frequency. This plan additionally gives the system operator adaptability to plan the generation in an ideal way. In this examination, the execution of a Proportional Integral (PI) controller is proposed because beneficial AGC of 2 area thermal and thermal deregulated system works under the impacts of bi-lateral contracts over the dynamics. The tuning of PI controller parameters is illuminated by utilizing a Moth-Flame Optimization (MFO) algorithm. Further to improve the AGC performance, the Hydrogen Energy Storage (HES) units is incorporated into its control area which can adequately moist the electromechanical motions in a power system, as they give guarantee from the storage limit notwithstanding the generator rotors dynamic energy which can share abrupt deviations in power requirement. The Thyristor Controlled Phase Shifter is proposed in arrangement with tie line between any inter-connected areas that may be applied to balance out frequency motions of the area by fast control of power in tie line over the interconnections. Execution of HES-TCPS units' blend captures the underlying frequency fall just as the power deviations in tie line for an abrupt load unsettling influence and the outcomes show that the charges of UI are extensively limited while keeping up at normal frequency worth. Furthermore, proposed strategy yields an eminent decrease in the control input deviation yet, in addition, guarantees superior soundness for the unscheduled interchange price signals therefore, the market participants can get benefit accordingly.

Contribution of frequency linked pricing control on ALFC and AVR power system integrated with DFIG based wind farms

This research article presents the participation of frequency linked pricing control (FPC) scheme for frequency and voltage control ancillary services in multi-area power system having automatic load frequency control (ALFC) loop and automatic voltage regulator (AVR) loop and integrated with doubly fed induction generator (DFIG) based wind farms. Mutual coupling effects are shown between the two loops by extending linearised ALFC system to include excitation model using AVR loop. FPC based on availability based tariff (ABT) mechanism is used under small load perturbations in power system to provide secondary control to reset frequency and voltage to their nominal values. Dynamic participation of DFIG based wind farms is shown by using modified inertial control scheme to inject active power quickly into the power system, thereby arresting deviations in frequency and voltage during transient conditions. Results reveal that coordinated action of DFIG based wind farms under FPC environment provides better dynamic frequency and voltage responses by reducing their deviations from nominal values.

RETRACTED ARTICLE: Analysis of antlion optimizer-based ABT for automatic generation control of an interconnected power system

In this paper, a novel ant lion optimization algorithm is proposed for the recent availability-based tariff (ABT) pricing scheme for the automatic generation control of a three-area interconnected power system (IPS). The innovative ant lion optimizer (ALO) process is performed in conjunction with ABT. The real frequency and load variation are realistic to the input of ALO and minimize the objective function area control error, generation costs and marginal cost of the system. Based on the output of the ALO, the ABT is resolute and assumed as the input of the proposed controller. The dynamic performance of the three-area IPS values including hydrothermal, wind turbine and photovoltaic power systems are evaluated on the basis of limits such as frequency deviation, generation power and tie-line power. Based on these limits, the frequency deviation is controlled and the parameters of the multi-resolution PID (MRPID) controller are regulated. The proposed MRPID controller is modified with the proposed ABT-based ALO to increase the optimal resolution. A three-area IPS is modeled under numerous loads to improve the efficiency of the proposed algorithm. The performance of the this method is demonstrated and compared with existing methods including particle swarm optimization and gravitational search algorithm.

A novel operating strategy for unscheduled interchange price-based automatic generation control

In order to maintain grid discipline and bring about more responsibility and accountability among the participants in the system, the availability-based tariff (ABT) mechanism was introduced in Indian power sector. Though there is a considerable improvement, it is further required to maintain the system with greater frequency stability and reduced fuel cost for power generation. This paper presents a control scheme for unscheduled interchange (UI) price-based automatic generation control (AGC) to nullify the deviations in frequency following a disturbance in the system. This scheme gives the system operator flexibility to schedule the generations in a desired manner on various units by which the merit order dispatch can be maintained. The proposed scheme is tested on a single area system with four generating units and is compared with an existing system and found effective. The results indicate that the frequency is maintained at normal value following a disturbance and the increased load can be shared among the generators in a desired manner.

Price based fuzzy automatic generation control for Indian tariff system

In order to maintain grid discipline and bring about more responsibility and accountability among the participants in the system, the availability based tariff (ABT) mechanism was introduced in Indian power sector. Though there is a considerable improvement, it is further required to maintain the system with greater frequency stability and reduced fuel cost for power generation. This paper presents a new control scheme for price based automatic generation control (AGC) to minimize the unscheduled interchange (UI) charge through nullifying the deviations in frequency and to maintain the generation at various units economically following a disturbance. This scheme also gives the system operator flexibility to schedule the generation in a desired manner. A two input single output Mamdani type fuzzy PID (FPID) controller is used in the proposed scheme to improve the system dynamic response. The proposed scheme is tested on a single area system with four generating units and is compared with an existing control scheme and found effective. The results indicate that the UI charges are considerably minimized by maintaining frequency at normal value and the load perturbations can be adjusted among the generators in a desired manner following a disturbance.

Frequency Based Risk Assessment of a Power Producer in Indian Electricity Market

AbstractThe power producers in Indian electricity market face risks pertaining to real time frequency deviation and spot price volatility. An increase in real time demand lowers the system frequency. This forces the producers to draw unscheduled interchange (UI) power by paying a penalty, known as availability based tariff (ABT). The paper proposes a novel framework for optimal portfolio strategy selection of a power producer using uncertainty of frequency deviation and spot electricity market. Mean variance portfolio theory is used to model the stochastic optimization problem. In Stage 1, the operational ABT uncertainty structure is modeled and optimization is performed to determine optimal portfolio allocation, considering spot market and bilateral contract as available trading options. In stage 2, optimal involvement of options to hedge the cost side risk of unscheduled power interchange (UPI) is studied. Spot price volatility is introduced during hedging analysis and mean absolute percentage error (MAPE) technique is used to forecast the spot price range. A stochastic pseudo inspired particle swarm optimization (PIPSO) technique is proposed for enhanced profit-risk tradeoff. The model reflects that, spot and option trading could offer high risk protection vis-à-vis bilateral contract and can predominantly help in managing frequency penalty risk.

A novel approach for UI charge reduction using AMI based load prioritization in smart grid

System frequency is vital part for power system balance. As per India Electricity Grid code frequency should be in the range of 49.5Hz–50.5Hz. Deviation from above mentioned range is charged as Unscheduled Interchange (UI) charge. This paper proposes a new method for load and frequency control based on control of third parameter of three-part Availability Based Tariff (ABT) i.e. Unscheduled Interchange charges. New circuit is designed considering prioritization of load and using Advanced Metering Infrastructure (AMI) under Smart Grid environment.

A Novel Approach for a Two Area Load Frequency Control in a Competitive Electricity Market Adopting Unscheduled Interchange Price

This paper proposes a novel price based load frequency control scheme for a two area system, using an Unscheduled Interchange (UI) price signal, which is ideal and suitable for electricity market. The Government of India has introduced Availability Based Tariff (ABT) structure with an intention of ensuring grid security and to regulate grid indiscipline through Central Electricity Regulatory Commission Regulation. After the introduction of this regulation, the over or under injection by the generating companies (GENCOs) during off peak or peak hours are demoralized and the frequency is maintained at the nominal value. In this paper, the GENCOs instead of reacting to this price signal manually, an automated mode of frequency control is deployed in each area using UI price signal to achieve fast response to load change. The Distribution Company (DISCO) Participation Matrix (DPM) has also been employed in this work to relate the scenario under deregulation of electricity market. The proposed scheme has been verified for different cases by simulating it on a two area system, each having four GENCOs and one DISCO in MATLAB/SIMULINK environment. From the results, it is clearly observed that if the proposed method is employed by all GENCOs, it will certainly enhance the control of system frequency and at the same time throw down the UI liability of market participants. It also ensures that the GENCOs and DISCOs strictly adhere to the bilateral contract following the DISCO participation matrix.

Economic analysis of Indian pumped storage schemes

Pumped-hydro energy storage schemes (PHES) are developed for improving the net efficiency of the base load thermal power plants. These schemes are operated only at times of peak demand and during major power plant outages. In India, the first pumped storage plant was commissioned during 1985 and till today eleven plants with on aggregate installed capacity of 4804MW have been in operation. However all these plants up to the year 2003 have generated energy less than the projected figures. The major reason for less output from the PHES in India, than that envisaged in the planning stage is deficit of off-peak power availability for pumping operation in almost all the regional power grids except north-eastern grid. But gradual increase in efficiency has been realized from PHES operation after introduction of the availability based tariff (ABT) in 2003. Further, the increase in peak power demand, requirement of spinning reserve, increased generation from renewable energy sources have singly and combinedly triggered the necessity for installation of more pumped storage schemes in the country. Under these circumstances, this analysis addresses the economics of pumped storage schemes in India with special reference to Kadamparai PHES. Various costs involved in pumped storage operation are analyzed in the Indian context. The case study reveals considerable techno-economic benefits obtained by more operational hours of the PHES in the state grid after 2003. The analysis and results would be useful for investors and researchers to understand the economics of Indian pumped storage schemes.

Impact of frequency-based tariff in power market

System frequency can be a useful signal in real–time power system operation to promote competition along with operational reliability. The commercial mechanism adopted in India, the availability–based tariff (ABT), defines a power tariff structure that allows recovery of capital cost and fuel cost as well as a condition–based price incentive to participants which help to minimise the real power imbalance. We propose a mathematical model for profit–based dispatch and a heuristic technique has been developed to determine the daily scheduling of declared capacity by maximising the profit. The main purpose of the paper is to look at the advocacy rules of ABT more strategically and to develop plans for generation scheduling. Comparative analysis with previously followed two–part tariff system is also carried out to expose the importance and role of incentive/penalty for self regulatory system.

Optimal generation scheduling in power system using frequency prediction through ANN under ABT environment

In a competitive and deregulated power scenario, the utilities try to maintain their real electric power generation in balance with the load demand, which creates a need for the precise real time generation scheduling (GS). In this paper, the GS problem is solved to perform the unit commitment (UC) based on frequency prediction by using artificial neural network (ANN) with the objective to minimize the overall system cost of the state utility. The introduction of availability-based tariff (ABT) signifies the importance of frequency in GS. Under-prediction or over-prediction will result in an unnecessary commitment of generating units or buying power from central generating units at a higher cost. Therefore, an accurate frequency prediction is the first step toward optimal GS. The dependency of frequency on various parameters such as actual generation, load demand, wind power and power deficit has been considered in this paper. The proposed technique provides a reliable solution for the input parameter different from the one presented in the training data. The performance of the frequency predictor model has been evaluated based on the absolute percentage error (APE) and the mean absolute percentage error (MAPE). The proposed predicted frequency sensitive GS model is applied to the system of Indian state of Tamilnadu, which reduces the overall system cost of the state utility by keeping off the dearer units selected based on the predicted frequency.

Economic-emission load dispatch in renewable integrated system under availability based tariff (ABT) environment

Grid discipline is very important for smooth and secure operation of any power system. ABT is one such commercial tool which improves the grid discipline by suitably re-dispatching the participating generating units depending upon the frequency of the grid at different intervals. This paper presents a load dispatch model based on ABT, where any unscheduled interchange (UI) from generating units, which helps in maintaining nominal frequency on the grid, invites higher incentives. Besides load variations, the integrated unpredictable renewable sources like the wind and the solar units cause significant UIs and consequently vary the system frequency. The optimum sized pumped storage (PS) unit used in the generation mix compensates these variations, and reduces the UIs and emission. The study has been carried out for restructured power system with significant renewable sources integrated in it. The system frequency is predicted considering the variations in the wind power and in the load demand, and scheduled interchange (SI) power is decided based on the predicted frequency. The grid power schedule decided on the basis of predicted frequency is very useful in minimizing the UI charges. The PS unit improves the frequency profile by suitably adjusting its operation as pump and as generator, which minimizes the cost paid as UI charges. The results of the model proposed have been demonstrated on modified IEEE-14 bus system data.

Optimum scheduling of micro grid connected wind-pumped storage hydro plant in a frequency based pricing environment

This paper presents a new formulation to maximize the operational profit of a micro grid connected hybrid system having wind farm and pumped storage unit for a day ahead electricity market in a frequency based pricing environment. Under frequency based pricing mechanism in India, the pricing for energy exchange is adaptive as per Availability Based Tariff (ABT) rate structure and the payment for deviation from schedule, i.e. Unscheduled Interchange (UI) charge is inversely proportional to the prevailing grid frequency. In this work, a small power system is considered as micro grid and it is expected that the hybrid system connected with the micro grid has a role to play to maintain the micro grid frequency. The pump storage hydro plant is operated to serve the dual role of minimizing the UI flow and maximizing the system economy by participating in frequency control based on energy price. The uncertainties in wind power prediction and loads are considered. The optimum operating schedule of PSH unit in coordination with wind farm is investigated. The optimization is performed by utilizing the water storage availability of pump storage hydro unit. An optimization algorithm is proposed and solved using Artificial Bee Colony algorithm. The solution of the proposed approach gives the strategies to be followed by the hybrid system to operate its pump storage unit. The effect of the initial storage water volume on the performance of the hybrid system has also been investigated. It reveals that the PSH units would not operate simply to compensate for the short fall or the surplus generation of the wind units in a frequency based pricing system. Rather, the pump storage units should take the advantage of the low price periods to maximize the profit of the hybrid system. The hourly energy management scenarios of the hybrid system with the micro grid are reported and the numerical case studies on PSH plant scheduling demonstrate the effectiveness of the proposed approach.

Automatic generation control scheme for frequency linked price signal followed in India

Indian electricity market has adopted a concept of frequency linked commercial tariff system, commonly referred to as availability-based tariff (ABT), where variation in system frequency is used as market signal to encourage utilities to change generation in real time operation. As frequency varies with real power imbalance, proper incentive is rewarded for automatic generation control (AGC) service provided by the generating utility for making up the real power mismatch. In ABT, the rate of unscheduled interchange (RUI) for AGC service is fixed depending upon the frequency condition prevailing at that time. The conventional AGC system though tries to bring the frequency error to zero but it would be an ineffective solution for participating generating utilities under ABT since incentive/penalty varies with frequency. This paper investigates the rules and advocacy of ABT more strategically and develops a model for AGC based on conventional if-then logics for load-frequency regulation scheme that will respond to the frequency-based price signal in a profitable manner. The proposed model is tested on IEEE 14 bus system and part of northern region grid of India.