Increasing Load Demand Research Articles

Substations power quality improvement by flexible alternating current transmission system devices

<p>The increase in load demand has a negative impact on power system quality, reliability, and stability. Transporting reactive power from the generating side to the distribution side reduces the transmission line’s capacity to deliver active power to loads. In conventional power systems, during faults or sudden loads, the load flow changes and causes extra voltage drop. Reactive power compensation at the load side can improve voltage quality at distribution busbars, but the conventional compensation method doesn’t offer the required flexibility. With the development of the power electronics industry, flexible alternating current transmission system (FACTS) devices have been introduced. There are many categories for FACTS controllers, including series, shunt, and hybrid, which can exhibit dynamic operating characteristics. In this paper, two types of FACTS devices (STATCOM and fixed capacitor-thyristor-controlled reactors (FCTCR)) have been used to improve voltage profile in a part of Iraq’s high voltage power system during unusual operating conditions, such as sudden loads and the absence generation. Load flow calculations were conducted to determine the critical bus, and then the performance of the FACTS devices was investigated during heavy loading when the devices were connected separately to the critical bus. The voltage drop in the bus was 1.58%, which reduced to 0.78% with STATCOM and 0.96% with FCTCR.</p>

Benefits maximisation of Distribution Company by optimum deployment of renewable energy source and DSTATCOM

Now-a-days, with the worldwide economic boom, there has been a steady increase in load demand, which further reduces voltage magnitude of mainly tail-end buses and increases losses. Further, the profit margin of the Distribution Company (DISCO) has also come down and providing reliable power supply has become a major concern. Under this circumstance, this study proposes an analytical method to accomplish the optimal integration of solar DG and DSTATCOM to enhance techno-eco-environmental benefits. Instead of traditional soft-computing techniques, a simple, easy to implement and computationally efficient analytical technique is proposed to carry out the device incorporation process. To find suitable locations for device placement, a new and innovative formula called Device Location Selection Index (DLSI) is developed. To properly design scenario, uncertain nature of DG’s output and load is considered. A meticulous performance analysis is presented considering different scenarios to facilitate DISCO with an optimal strategy.

A Gershgorin Circle Theorem Inspired Controller for Renewable Energy Source Integrated Power Systems and Multimicrogrids

Increasing load demands, variations in the operating conditions, continuous integration of the renewable energy sources constitute a multifarious challenge for the researchers to maintain the quality in performances of a load frequency controller. To contemplate such issues, a Gershgorin circle theorem inspired controller assimilated with the particle swarm optimization is proposed for multiarea power systems. The proposed method ensures system stability while abating the frequency variations in the operational areas and the power deviations in the interconnected tie-lines. The present analysis is substantiated through an interconnected photovoltaic (PV) integrated thermal power systems. Furthermore, the competence of the proposed method against increasing complexities is validated by considering an interconnected multimicrogrid systems consisting of renewable and nonrenewable energy sources. The performances of the proposed controller are demonstrated considering fixed and time-varying load disturbances, and fluctuations in renewable energy sources. Results corroborate that the proposed method is successful in maintaining the system stability while mitigating the frequency and the power deviations in all such operating conditions. A comparative analysis of the proposed method with prevalent control techniques (e.g., PI and PID-based controllers, tilt–integral–derivative, integral–tilt–derivative) and optimization algorithms (e.g., genetic algorithm, gravitational search algorithm, imperialist competitive algorithm) is presented to highlight the substantial performance improvements in the considered systems.

A novel loss allocation method applicable for any desired network topology

Due to the expansion of power networks in response to the increase in total load demand, the complexity regarding power systems transmission networks’ configuration has been increased. Similarly, with the advent of local energy markets and transactive energy concept, power distribution networks are undergoing a fundamental change. In this respect, numerous agents are transacting power within both distribution and transmission networks. Therefore, as more power is transacted among agents in different energy networks, power networks face higher power losses. Dealing with the financial outcomes of these losses, a general accurate yet fast method for loss allocation in power networks is of utmost importance. In response, this paper proposes a novel loss allocation framework based on the power tracking method that is applicable for any desired network topology within both transmission and distribution networks. In this regard, at first, a new method is proposed to obtain how the optimal scheduled generation of each production unit should be allocated to each specific load of the network. Then, it is obtained that how these transactions are flown in each line of the network. In the next step, the exact losses in each line resulted from distinct transactions between each pair of agents in the network are obtained. Finally, how each specific transaction contributes to the total losses of the network can be calculated. By implementing the proposed framework on a modified IEEE 14-bus test system and a 69-bus IEEE distribution network, the applicability and effectiveness of the proposed method is demonstrated by the numerical results. The results indicate that the proposed method can be implemented in any network and with any scale.

Role of hydro generation in Indian power grid to challenge the uncommon load patterns during crisis

Recently, the Indian Prime Minister Appeals to switch off the Light by people during the corona outbreak for 9 min. It also provides a significant challenge to the Indian power grid. A small malfunction of the power system may lead to a huge disaster that may worsen the daily activity of the 100 million people along with the pandemic. This review work discusses the actions of Indian power grid operation during the challenge when all the domestic Light loads are switched off for 9 min from 21:00 Hours. POSOCO (Power system Operation Corporation) of India handled the difficulty using effective actions and logged the total reduction in all India demands of about 31,089 MW (31 GW) during the event. Before the event, Indian power demand started dropping from 20:45 Hours and reaches 85,799 MW at 21:10 Hours. Subsequently, after the event, the demand begins inclined and settled around 114400 MW at 22:10 Hours. During this complete process, the grid frequency remained between 50.26 Hz and 49.70 Hz. On the other hand, the preliminary mock exercise was conducted by POSOCO before the day of the actual event and reported the expected load reduction of 15085 MW. It was anticipated by summation of SLDCs (State Load Dispatch Centers) which was half value with reported load reduction during the actual event and shows higher variance. This article also interpreted the reports of POSOCO and estimated that the actual Load reduction of this event was about 27452 MW taking place for 15 min. From the discussions, it is observed that the hydro generation schedule have the potential to minimize the havoc of the power system during steep increase and reduction of load demand during unexpected natural or artificial calamities.

Effect of OLTC Transformer on Voltage Stability Improvement

The voltage stability is a major concern due to increase in load demand. Therefore proper planning and operation is required. For stable operation of power network extensive voltage stability analysis is very much essential. This necessity is largely due to the current trends towards system operation under stressed condition, this is because of the increase in load demand. In this paper, a method has been developed how, with the help of OLTC Transformer voltage stability can be improved and it is tested on IEEE 14 bus system. Result shows the effectiveness of the method.

Novel PID Controller on Battery Energy Storage Systems for Frequency Dynamics Enhancement

Frequency dynamics is one of the important aspects of power system stability. From the frequency dynamics, the operator could plan how is the reliability of the electricity. The frequency can be maintained by controlling the balance between load demand and generation. To maintain the balance of the generation, the governor is playing an important role to increase the speed of the turbine and enhance the generating capacity of the generator (ramp-up). However, as the speed of the governor is slower than the increasing load demand, in the sub-transient area, the frequency may experience higher overshoot. Hence, it is important to add additional devices such as battery energy storage systems to enhance the frequency dynamics response in the sub-transient area. One of the important parts of storage is the controller. The controller must make sure the storage charges and discharge energy are in the sub-transient area. Hence PID controller can be the solution to make the storage operate optimally This paper proposed a novel PID controller on battery energy storage systems (BESS) to enhance the dynamics performance of frequencies. The five-area power system is used as the test system to investigate the efficacy of the proposed novel idea. Time domain simulation is investigated to see the improvement of the frequency dynamics response. From the simulation results, it is found that adding a PID controller on BESS could enhance the BESS response and result in frequency dynamics response improvement.

SMART DISTRIBUTOR SYSTEM FOR MICRO GRID CONTROL

A smart distributor system for controlling a micro grid has been developed in this work. The system switches ON different generators one after the other as the consumer load demand increases or switches them OFF one after the other as the consumer load decreases. This was achieved using a microcontroller, current and voltage transformer. The microcontroller was programmed using embedded C-language to communicate with the current and voltage transformers to give necessary output signals to activate or deactivate the generators. In this design, the maximum load demand of each generator was placed at 60W-100W (Generator 1), 100W-160W (Generator 2), 160W-220W (Generator 3), 220W-280W (Generator 4) and 280W-340W (Generator 5). The system was developed and tested by connecting seven 220V AC, 60W bulbs in parallel to the output of the generators. When the first generator having a capacity of 60KVA is switch ON, the Liquid Cristal Display (LCD) reads 0KVA meaning that no load is connected to the generator. As the generator is loaded by connecting each of the lamps to it, the LCD displays the total load connected to the generator. When the total load exceeds a certain amount (100W decided in this experiment as reflecting the maximum capacity of the first generator) the micro-controller sends a signal to activate another generator to accommodate the load demand. This system continues to automatically add generators to the grid as the load demand increases. Also, as the load connected to the generator decreases, the micro-controller sends signal to deactivate the generators one after the other.

Dynamic Reactive Power Optimization Configuration of New Energy Power Station Based on Fault Limit Removal Time

The large-scale construction of long-distance, high voltage level transmission projects and sustained load demand increase negatively influence transient voltage stability. A certain amount of dynamic Var compensation at the receiving end of the power grid can significantly improve the stability. Most new energy power plants, such as wind power, and photovoltaic generation, have installed dynamic Var compensation devices. The potential for safety and stability control should be fully exploited. In this paper, it is concluded that the critical fault clearing time is the main index to measure the transient voltage stability of the system, and the critical fault clearing time has been extended by allocating dynamic Var compensation. According to these conclusions, a method for optimal allocation of dynamic Var compensation to improve critical fault clearing time is proposed. The method has determined the optimal capacity and the installation point. The effectiveness of the proposed method is illustrated through simulations on the actual power grid.

Power Quality Improvement in Multifeeder Using MC-UPQC

Power Quality (PQ) issues have been a major concern as there is increased load demand and usage of variety of nonlinear loads. The innovation of Flexible AC Transmission System (FACTS) devices is a great way of solving PQ issues. Many devices like UPFC, D-STATCOM, and TCPST are emerging and are widely used for PQ improvement. In this paper, the Multi Converter Unified Power Quality Conditioning (MC-UPQC) System will be used for improving PQ in multi-bus systems. The system of MC-UPQC contains one shunt and two series Voltage Source Converter (VSCs). The conventional methodology contains one shunt and one series static devices. In the proposed methodology, two series VSCs will be used for further reduction of overall THD value. The simulation results of a reduction in THD and an improvement in PQ are compared with and without the proposed using MATLAB. Keywords—PQ, MC-UPQC, series VSC, shunt VSC, MATLAB.

Economic scheduling of virtual power plant in day-ahead and real-time markets considering uncertainties in electrical parameters

The virtual power plant (VPP) concept, which offers energy efficiency, benefits significantly from the tremendous potential of integrating distributed energy resources (DERs). This work proposes optimal economic dispatch of virtual power plant (VPP), and the problem is formulated in a novel way considering the potential of energy storage systems (ESS) of electric vehicles (EVs) and data center (DC) in a data center facility test model using optimized energy management system (EMS). The problem is evaluated for maximizing the revenue for VPP considering market prices and the uncertainties in the distributed energy resources. To this purpose, a techno-economic analysis of the proposed test system of VPP is evaluated using mixed-integer linear programming (MILP). Renewable generation, electricity price, load demand, and real-time EV behavior uncertainty analysis are forecasted using Long Short-Term Memory (LSTM) along with DC battery degradation analysis which constitutes the optimization model. The results showed that the VPP EMS can perform optimal power scheduling with the day ahead and real-time electricity price scenarios. Moreover, further analysis including battery degradation cost of DC UPS ESS proved the capability of the proposed framework by up to 2064.4 $/h revenue for day-ahead price and 562 $/h revenue for the real-time price compared to revenue without battery degradation cost. A simulation scenario is also carried out where the constant load demand and the battery storage powers are varied between 50% and 150%. It can be concluded that the 500 kW and 750 kW ESS (100% and 150%) are better choices as compared to 250 kW (50%) during increased load demand for investors due to their higher revenue. Hence it is concluded that this research highlights the importance of revenue benefits from deploying VPP with the collaborative operation of DERs.

Computational modeling of the axial behavior of corroded and buckled short steel piles strengthened using concrete-filled GFRP jackets

Steel columns or piles commonly used in bridges and marine structures in various parts of the world exhibit insufficient strength due to increased load demands or section loss due to corrosion. The latter issue can cause unexpected buckling of these columns. In this study, the repair of corroded and buckled short steel piles using concrete-filled GFRP jackets was numerically simulated to better understand the overall effectiveness of the method and the influence of the parameters involved. Thirteen steel piles used in this study had different degradation characteristics to investigate the section losses affecting the axial capacity and failure modes. The parameters considered included the presence or absence of concrete steel reinforcement (rebar), the diameter of the rebar, the number of GFRP layers, the location of the worn zone in the steel section and the severity of the section loss. The numerical models were validated using these experimental results of the repaired specimens from the authors’ earlier work on the topic. The main contribution of this study is in the development of the numerical models that can very accurately simulate the ultimate strength and damage behavior of retrofitted piles that are heavily corroded and buckled. The validated models were used in a parametric study to understand the effects of different levels of concrete strength, or corrosion of the piles in the flanges, the web, or both. The results of the parametric study provided further understanding of the structural behavior of degraded and strengthened steel piles.

Modeling and control of islanded DC microgrid fed by intermittent generating resources

In this paper an islanded microgrid fed through the wind and solar energy resources is presented. The power flow within the microgrid is controlled using a Neutral Point Clamped Dual Active Bridge (NPC-DAB) converter. In the proposed dc microgrid, the solar energy source is associated at the low voltage (LV) bus and the wind energy source is connected at the high voltage (HV) bus. A permanent magnet synchronous generator (PMSG) machine is used in wind energy conversion system. The real time solar radiation and wind speed data of Rupangarh, Rajasthan, India is used as an input for renewable energy resource. The NPC-DAB will work as a power electronics juncture for expediting the energy exchange in the islanded DC Microgrid. The proposed closed loop controller based on the capacitor voltage and load voltage will expedite a complete automatic operation of the islanded DC-microgrid considering various load changes. The system is studied without storage element as the automatic control of energy generation and load feeding is carried out by the NPC-DAB, also this makes the scheme cost effective. The optimum duty ratios for NPC-DAB operation are obtained and thus the increased load demand is met. The modeling of PMSG, NPC-DAB and wind energy system is discussed in details in this work. The proposed system is studied in MATLAB/Simulink environment and results are obtained for different load variations. All the wind control parameters, NPC-DAB waveforms, load waveforms are also plotted using MATLAB.

Transient stability enhancement using optimized PI tuning of static synchronous series compensator in wind power conversion system

Power systems are expanding comprehensively with the increase in load demand from both residential and industrial usage. Renewable energy is penetrating the power system to satisfy the power needs of the load demand. With its potential to generate power and compensate for a large portion of the load demand, wind generators make a major renewable power contribution. Power oscillations inherent in wind generator integration with the grid are a power quality issue to be addressed. Oscillation damping using flexible AC transmission system (FACTS) devices is a relevant solution for the power quality issue. There are multiple reasons for power oscillation. Mainly, power systems encounter fault conditions. The faults can be cleared, and the power system tries to retain stability. Sometimes, the system fails due to a longer settling time. A series-connected FACTS device utilized as a series compensator is referred to as a static synchronous series compensator (SSSC). Controlling the flow of electricity over a transmission line using this method is incredibly efficient. The capacity to switch between a capacitive and an inductive reactance characteristic is necessary. The SSSC regulates the flow of power in transmission lines to which it is linked by adjusting both the magnitude of the injected voltage and the phase angle of the injected voltage in series with the transmission line. This allows the SSSC to manage the power flow in the transmission lines. It does it by inserting a voltage that can be controlled into a transmission line in series with the fundamental frequency. This paper develops the optimally tuned SSSC in the wind-integrated grid system to dampen the oscillation. Teacher–learner-based optimization (TLBO) and gray wolf optimization (GWO) algorithms are used to tune the PI controller to improve the damping response. The obtained results show that the damping performance of the proposed controller is better than that of the other traditional controllers.

Design Coordination of a Fuzzy-based Unified Power Flow Controller with Hybrid Energy Storage for Enriching Power System Dynamics

In power networks, operation planning has become necessary due to the continuously increased load demand. The Unified Power Flow Controller (UPFC) controls the power flow through the network and improves the dynamics of the power system. In this paper, the design application of the coordination of a fuzzy-based UPFC with hybrid energy storage has been proposed to enrich the system's dynamic performance during abnormal conditions and improve the hybrid energy storage performance during transients when the DC link voltage is insufficient to meet the converter voltage demand. The hybrid energy storage consists of a supercapacitor and a battery connected across the UPFC Vdc shunt capacitor. The proposed system to improve the UPFC performance during large disturbances on a multi-machine system was designed and tested in MATLAB/SIMULINK.

Techno-Economic-Environmental Assessment of an Isolated Rural Micro-Grid from a Mid-Career Repowering Perspective

Pakistan is an energy deficient country with depleting energy reserves and increasing energy demand. Due to excessive population growth, the domestic and commercial energy sectors are experiencing rising demand. To meet the requisite demand, renewables are favored rather than conventional counterparts. In this study, we model hybrid power systems using solar, wind and biomass resources for electrifying remote areas. The four locations are chosen for the study around a developing country, Pakistan, where each site is designed according to an isolated microgrid with maximum indigenous resources potential as per the requisite demands. A survey is conducted for the load demand and biomass availability. Optimization is conducted across objectives of minimum levelized cost of the generated energy, least the net present cost and lesser payback period. The optimal results were achieved in-terms of required objectives across southern sites as compared to northern counterparts. The cost of generated energy is comparable to grid electricity and ensures 24 h power supply without cut off and load shedding to the un-electrified rural area. The hybrid power system has a low carbon footprint across emissions due to the use of renewable resources. All the estimated load of rural communities is met with the available resources and mid-career impact has also been conducted across 10 years of the project life to fulfill the increasing load demand of the communities after installation. The results are validated via comparative analysis and show the effectiveness of the proposed study.

Advanced optimizer for maximum power point tracking of photovoltaic systems in smart grid: A roadmap towards clean energy technologies

With the increased load demand and generation cost of electricity, renewable energy sources (RES) provide cost effective and environment-friendly solution. Integration of solar energy includes the challenges of finding the Maximum Power Point (MPP) to achieve the maximum power from the solar. Combining RESs with distributed generation (DG) comes with the challenges of voltage regulation and frequency mismatch. In this work, a novel approach of Robust Antlion Optimizer (ALO) algorithm is implemented for MPP tracking in solar photovoltaic (PV) system and charge controllers are designed for storage system while the DC to AC converters have been designed to match RESs’ frequency with that of DG. Power scheduling is done to decrease operational cost while keeping the voltage and frequency in the allowable range. Research findings provide useful policy implications for all stakeholders to meet energy needs in a consistent and coherent manner.

Impact Analysis of Distributed Solar Photovoltaic Power Generation System Integration on Power Grid Voltage Stability Using Static Techniques

Recently, the rise in consumption of electrical energy and power transmission between various utilities has resulted in the emergence of anxieties about the power system's network voltage stability. Additionally, the necessity for power systems to perform in a secure condition has increased due to an increase in load demand globally. Therefore, the use of renewable energy-based distributed generation is growing quickly to help meet electrical demand and disrupt environmental issues caused by the use of fossil fuels. This type of generation can have a positive or negative influence on the stability of the power system. This paper analyzes the effects of distributed PV power integration on the power grid's voltage stability using static techniques. In order to improve efficacy and accuracy, give a complete and in-depth understanding of the problem of voltage stability, and identify the causes of instability, a combination of four different techniques is employed for analysis. Analysis methodologies include modal analysis, sensitivity analysis, PV curve, and QV curve. The analysis of voltage stability is carried out on an IEEE 14-bus system by using NEPLAN software. The simulation results showed that the integration of a renewable energy resource-based distributed solar PV power system into the test system led to a noticeable improvement in stability degree, a decrease in sensitivity of buses, a significant improvement in system MW loading, an enhancement in voltage profile, and a perceptible increase in reactive power margin

Transmission Network Loss Reduction and Voltage Profile Improvement Using Network Restructuring and Optimal DG Placement

This paper introduced a method using hybrid combination of network restructuring and optimal placement of optimally sized distributed generators (DG) to reduce loss and improve voltage profile in a practical transmission network for scenario of high load demand for a period of ten years. A study is performed for four study cases which includes the test transmission network without considering optimal DG placement and network restructuring, considering network restructuring, optimal placement of DG units using proposed grid parameter oriented harmony search algorithm (GPOHSA) and considering hybrid combination of network restructuring and DG placement using GPOHSA. Network restructuring is achieved by addition of a new 400 kV Grid-substation (GSS) and a 220 kV GSS along with associated transmission system. GPOHSA is obtained by a modification in the conventional harmony search algorithm (HSA) where grid coordinates are used for locating the individuals in an objective space. Performance Improvement Indicators such as real power loss reduction indicator (SPLRI), reactive power loss reduction indicator (SQLRI) and summation of node voltage deviation reduction indicator (SNVDRI) are proposed to evaluate performance of each case of study. The period of investment return is assessed to evaluate the pay back period of the investments incurred in network restructuring and DG units. It is established that hybrid combination of network restructuring and DG units placement using GPOHSA is effective to meet the increased load demand for time period of ten years with reduced losses and improved voltage profile. Investment incurred on the network restructuring and DG units placement will be recovered in a time period of 4 years. Effectiveness of the GPOHSA is better relative to the conventional genetic algorithm (GA) for DG unit placement. The study is performed using the MATLAB software on a practical transmission network in India.

Optimal Deployment of Unified Power Flow Controller on Nigerian 330 kV Grid Using Artificial Bee Colony

Transmission line power loss minimization and voltage profile improvement are challenging problems in modern power systems due to continuous increase in load demand. In this paper, an optimal location and sizing of unified power flow controller (UPFC) to improve the performance of the updated 54-bus 330 kV Nigerian network was presented. Here, the maximum power loss bus was identified to be the most favorable location for fixing the UPFC under different loading conditions; slightly underloaded (90%), normal loading (100%) and slightly over loaded (110%). The optimum location was determined using the artificial bee colony (ABC) algorithm. The work was implemented in MATLAB® 2021b environment and its performance was evaluated based on the simulation results obtained. The simulation results revealed that, ABC proved to be robust based on the facts that all the voltage profile that violate ± 5% tolerance margin of the nominal voltage criteria were kept within the acceptable limit after the UPFC optimal deployment. Moreover, the proposed approach also recorded significant reduction in the overall active and reactive power loss in the entire network with a minimum percentage average active power loss reduction of 45.3% under different loading conditions.