Objective & Background
Grid-integration of fluctuating solar power requires forecast information on the expected power production as a basis for management and operation strategies. With increasing importance of photovoltaic (PV) power for the world-wide energy production, PV power prediction services are already an essential part of grid control and energy trading.
In this presentation we present an integrated combinational PV power forecast based on machine learning algorithms. The aim is to cover a wide range of forecast horizons from short term (i.e. several hours) to several days ahead. Also, the system shall be applicable both for single PV systems and grid controlling zones. The combinational forecasting system shall be used to optimize the grid and market integration of Renewable Energies.
The basis for the combinational forecast are three independent information:
NWP models are widely used for day-ahead forecasting. However, due to the high amount of computing time there are only few updates per day. So NWP shows limited accuracy for the next hours.
Short term (or intra-day) forecasts in this study are based on cloud observations from satellite. By comparing consecutive satellite images, and by means of pattern recognition, the speed and direction of cloud motion is derived. By integrating thermal (infrared) satellite observations, forecasts are also available in the morning hours where no information is available from images taken in the visual spectral range.
(Online) measurements of PV power production from monitoring systems are important information for the combinational forecast. They are used for the short-term adaption and lead to a significant reduction of the systematical error.
Finally, machine learning algorithms are applied to combine all three information depending on the weather situation and the forecast horizon.
Evaluations will be performed both for large portfolios (here: electricity grid controlling zone in Germany) and for single sites (here: reference PV systems in India). The evaluation covers different forecast horizons from few hours to day ahead. All results will be compared to real PV power production measurements.
One interesting result will be the forecasting accuracy for single sites as already now large PV plants are obligated to provide forecasts in many markets for grid security reasons.
Conclusion and Outlook
By using machine learning algorithms the accuracy of a combinational PV power forecast is expected to be better than each of the contributing forecasts for all forecast horizons. Further investigation is needed to fill the gap of information between the actual production (‘forecast horizon’ 0 minutes) and the satellite forecast (highest accuracy 1 to 2 hours ahead). So as an outlook the use of sky imaging cameras is addressed.
In the present scenario of huge demand for energy economy necessitates development of various energy resources either,conventional and non-conventional.Despite rapid depletion of fossil fuels across the world, billions of people are yet devoid of the comfort offered by electricity.If the consumption of fossil fuel continues at the current rate, the future generation is bound to suffer from the acute shortage.The associated global warming and ozone layer depletion caused due to intensive application of fossil fuels forces us to look for solar based systems.One such system is an Organic Rankine Cycle (ORC) plant which is modular and scalable. It can be easily transported, assembled and commissioned rapidly at site, may it be in small industrial units or “micro-grids” for remote and isolated areas. The heat-energy converter of the ORC plant is a hermetically sealed unit with a few moving parts. This technology now turns out to be proven and available to all. The plant requires no operator, the maintenance cost is negligible over long periods, and the unit can be operated and monitored remotely. The design, technologies and materials proposed to be used are largely indigenous and it acquires a significant improvement over the traditional units used earlier for large plants, thus it provides acceptable performance at low capital cost. The solar energy available for almost 295 days a year in India is utilized by an array of sun-tracking parabolic-trough collectors. The functionality and performance of such newly developed low-temperature ORC unit comprising of helical coil solar cavity receiver based parabolic trough concentrator (PTC) was investigated at CERD, Mechanical Engineering, IIT(BHU), Varanasi. The PTC comprised of blackened helical coil made up of two concentric borosilicate glass cylinder with vacuum in annulus was kept at focal line that maximized the conversion of energy received from sun into useful heat and eventually electricity.
As power systems around the world transform, power system flexibility has become a global priority. A range of operational, policy and investment-based interventions are available to render modern systems more flexible, thereby facilitating cleaner, and more reliable, more resilient, and more affordable energy. This report identifies challenges and opportunities to unlock system flexibility and accelerate power system transformation (PST) efforts. It provides an overview of the policy, regulatory and market instruments which can be implemented in different power sector contexts to mitigate these challenges. Importantly, all power system assets, including variable renewable energy, can provide flexibility services, if enabled by proper policy, market and regulatory frameworks. These assets include power plants, electricity networks, energy storage and distributed energy resources. A wealth of known strategies, approaches and instruments can be readily applied and adapted to power systems. These include modifications to: energy strategies; legal frameworks; policies and programmes; regulatory frameworks; market rules; system operation protocols; and connection codes. Moving forward, updating system flexibility policies to match the pace of technological development can help to accelerate global PST, while ensuring that all classes of power system assets are able to receive fair remuneration for the flexibility services they are capable of providing.
All power system assets can provide flexibility services if enabled by proper policy, market and regulatory frameworks. Even VRE resources are emerging as a flexibility resource. Several countries (e.g. Australia, Ireland, Spain and the United States) have introduced market reforms and regulations that activate VRE flexibility. In the United States, innovative flexibility retrofit investments have been demonstrated in existing conventional power plants, such as hybridisation with BESS. Moving forward, efforts to modify connection codes and market rules will be key for all assets – including power plants, electricity networks, DER and energy storage – to receive fair remuneration for their flexibility services.
Electricity networks remain a critical enabler of system flexibility. Various policy and regulatory instruments can de-risk new network investments in support of system flexibility, and promote more “system-friendly” deployment of VRE. In the United Kingdom, a “cap-and floor” regulatory regime mitigates investment risk in merchant interconnection projects by protecting investor in years with low market revenue in exchange for capping revenues in high revenue years.
Battery energy storage systems are becoming a cost-competitive flexibility provider. Regulatory innovations can help to unlock the multiple value streams of energy storage. Australia, the United Kingdom, the United States and the European Union’s Electricity Directives offer useful examples of regulatory innovations.
Anti-islanding protection is very important for modern inverters connected to utility. India is a fast growing economy with raising energy consumption through renewables having a target of 175 GW by 2020. This paper describes the anti-islanding protection function in a 20 kW solar-wind hybrid inverter with battery backup option considering only the solar input side connected at input and utility connected at output side. As per the Indian standard 16169 which was released in 2014, any power conditioning unit connected to utility must disconnect from utility within 2s after it goes off-line. The three different voltage levels and total of 31 conditions were simulated for various real and reactive power maintaining quality factor 1 at utility side through a 200 kW RLC load and the disconnection time of inverter were obtained through a high definition oscilloscope. For the inverter tested for anti-islanding protection function, it was found that in all scenarios the inverters disconnection time was well within two seconds as per the limit imposed by IS 16169:2014.
India has set a target of achieving 175GW generation through solar, wind and other renewable resources to be achieved by end of year 2022. In the near future when renewal penetration to the network will be sufficiently large, it will impose several challenges for grid operator. The issue of maintaining voltage profile during dynamic and transient grid conditions subsequent to renewable mix generation needs to be looked into, on top priority. The flexible generation due to unpredictable wind pattern and solar generation which sometimes varying in nature due to cloud movement, will impose a challenge to ensure the power quality and efficient grid operation. The additional large scale VAR control requirement due to solar and wind addition needs to be met by installing new VAR compensation equipments.This paper suggests use of spare generators stored at different projects as synchronous condenser to augment MVAR requirement of different regional grids. The investment to install synchronous condenser is much lower as compared to other FACTs devices, besides offering better performance under dynamic conditions emerging from renewable generation variations. The machine will also meet high short circuit current requirement and high inertia due to rotating heavy mass to take care of transient active power support.
Several large rating turbo-generators (500MW, 660MW and 800MW) are available and stored at different project sites in India. It may be noted that stator replacement of large unit has been very rare in past. Also the rewinding of generator can be done almost in same time span as required in case of replacement of large turbo-generator.
Condition of Generator insulation system- It has been seen that the condition of machine insulation system deteriorates, if it is not in operation and adequate measured for protection not taken during long storage. In absence of proper storage guidelines, many times these machines expose to poor environmental conditions causing insulation deterioration.
It is proposed to use these spare generators at location close to their site in respective regions as synchronous condenser to meet the VAR requirement of system during dynamic and transient conditions.This scheme will make the machine available in healthy condition, if required to meet any eventuality in future.
Major benefit of using spare 588MVA, 776MVA and 940MVA generators,will meet frequent MVAR support requirement. Also improving the grid stability and power quality. The synchronous condenser also has several advantages, especially high Short Circuit and inertia to handle transients and dynamic disturbances. The proposed layout plans in paper.
This paper describes the results of a GIZ funded project, where the possibilities to control active power and to provide ancillary services with renewable energies in South India were investigated. The project, which was conducted in the first half of 2019, was split into two work packages. First, a survey was conducted to find out the capabilities of wind and PV plants in South India to control their active power and to provide ancillary services. This included also the available communication infrastructure and options for retrofitting.
In the second work package, the regulatory framework, grid code and market design was analyzed. In the next step suggestion for improvement were drafted to implement active power control and provision of ancillary services by wind and solar power plants. To elaborate these recommendations international best practices from different countries have been analyzed.
Mostly we use PV modules are based on poly or mono-crystalline technology. The I-V Characteristic of Solar Module Indicates Open Circuit Voltage as Voc and Short Circuit Current Isc. The modules are arranged in series to achieve the required dc bus voltage and in parallel for increasing current. This combination of series and parallel modules forms PV array. At any time, there exists a unique operating point at which the power is at peak i.e. max. Power Point (MPP). MPP fluctuates continuously as irradiance and temperature varies. So MPP tracker (MPPT) is needed to ensure the maximum power is always extracted from PV array. Electrical Power Generation in Solar Module is totally dependent on Solar Irradiance. Due to Non-Linear output characteristic Fault Detection is quite difficult. Partial Shading condition will result into low power. Line to Line fault at low power is difficult to detect. OCPD’s are not capable to detect faults in every condition. GFPD’s Improper Operation. Line to ground faults at higher irradiance. Faults on DC sides and High DC arc. Renewable energy is expected to play an increasingly prominent role in Indian power sector in the coming decades and giving its various benefits. The main intention for this study is to emphasizing on Renewable Energy and to improve the performance of Solar Power Plant by providing almost better MPP Tracker. There were several papers are available for the field of solar and deferent methodology is implemented to improve the same. It is quite difficult to identify the fault location in Solar PV system and especially at DC side for PV arrays. Main functions of charge controllers are low voltage disconnection (LVD) to protect the battery from deep discharge and high voltage disconnection (HVD) to protect the battery from overcharging. To improve the performance of PV output MPPT algorithm can be applied by matching the PV array impedance and load impedance. In P&O an initial point is chosen and perturb (or disturb) until the value of the variable is increasing. When the value decreases stop perturbing. Move in the reverse direction to obtain the maximum value. The Incremental Conductance (IC) method locates MPP by differentiating the PV power with respect to voltage. MPP is located when the differentiation result is zero. A boost converter can be applied on both the PV and grid for regulating the output voltage.
The main objectives of this paper is to Improve the Efficiency and Performance of Solar PV Grid Tied System with IOT based Tools/ Machine Learning. Raspberry Pi and Arduino can be used for the same and Performance can be improved along with the same monitoring of each array is also possible. Fault finding and repairing can become easy task for Plant Operator. Shadow effects can be optimized using the same.
Transport is the largest consuming sector representing 40 per cent of total energy in the world. The recent development of electric and hybrid vehicles is potentially providing effective solutions to the reduction of the use in fossil fuel. As per forecast by International Energy Agency (IEA) in its Global Outlook 2018 report, electric car stock will be ~ 70 million by 2025. World Bank announced that it will stop financing upstream oil and gas projects after 2019 to raise funds to finance a shift towards clean energy. In this paper the research challenge is to optimize a novel framework for managing electric vehicle telemetry data through a process of AI based Algorithm to translate this data into useful engineering information for new, model-based, control system solutions for the vehicle‟s performance. Current and voltage are the most commonly used detection parameters for EVs. Apart from these, temperature, vibration, power, noises, and torque are also utilized on the basis of different detecting techniques. Overheating of electrical machines leads to rapid failure. Hence, the main limitation on electrical generators and drive is a temperature limit, which is generally enforced with an electrical fuse (current limit). The smart sensors once integrated into system give real time information allowing an unparalleled understanding. Furthermore, they may be used to investigate fast charging protocols and ageing. For any specific faults in Electric Vehicle like over charge / overheating, short circuit / open circuit of cell etc in Energy storage fault and abnormal connection of stator winding, O.C. or S.C. of stator winding, bearing failure, S.C. of rotor winding etc in Electric Motor fault. We can consider n no. of case and optimize the value of that specific fault by analyzing data of fault. By doing feasibility study and design optimization of all faults in Electric Vehicle for specific condition we can build prototype for mathematical model of EV and validate simulation results with experimental data through Lab demonstration model.
Building Transactive Energy Markets (TEM) to optimize Renewable and Distributed Energy Resources grid integration:
Growth of renewables and distributed energy resources (DER) such as large scale grid connected solar plants, solar PV with batteries, storage, EV charging points etc., and flexible consumption patterns at the edge of the grid offers a new opportunity for grid operators to optimize whole-system. If regulators, policy makers and grid operators plan to optimize grid operations for the benefit of every stakeholder then it is imperative for them to optimize utilization of these flexible supply and demand resources at all levels. However, it is easier said than done because these resources are growing at the high voltage as well as at the edge (medium/low Voltage level) of network, and traditional mechanism of whole-sale market valuation (based on average estimates) and centralized control (predominantly driven by transmission & high voltage level) might not work effectively to optimize these resources. There is need of a short term balancing market supported by retail transactive energy marketplace which is enabled by a distributed intelligent systems those facilitate real-time valuation of flexible services at the edge of the grid and federated control.
The Point of View (PoV) will discuss:
What is Transactive Energy and Transactive Energy Market, and key terminologies those we need to understand such as Control Mechanism, Economic Mechanism and Value to appreciate the TEM? How transactive energy markets can enable whole system optimization?
What is the drive, value and business case such as agile renewable integrations, Totex optimization, Carbon footprint reduction etc. for grid operators and regulators to implement transactive energy markets?
What are some key use case scenarios for Transactive Energy Markets for grid operators such as:
Once the context of TEM, benefits and use cases are defined then the PoV will discuss a roadmap to establish TEM. It will showcase enterprise architecture of a smart distribution system operator with IT-OT systems such as SCADA, ADMS, OMS, DERMS, AMI, GIS, MDMS, CRM and EAM. PoV will also focus on the role of cutting edge technologies such as Artificial Intelligence, Big data analytics, IoT and Blockchain to establish transactive energy markets, promoting optimization of renewables and DERs on grid.
Other aspects such as overall policy and regulatory vision-and-objective, roles and responsibilities (system operators, aggregator etc.), transactive parties, extent and scope of transactions, settlement rules for inter and intra jurisdictions etc. will also be covered as a part of discussion.
The concluding section will define a roadmap to achieve this journey.
The rising demand for power along with more sensitive and critical loads necessitates an increased installed generation capacity. Environmental problems and sustainability concerns make renewable energy sources (RES) integrated into the grid crucial for power system expansion in the future. Along with USA, China and the European Union, India has one of the largest and most ambitious renewable capacity expansion programs in the world. This includes the target of achieving 227 GW of electrical power (earlier 175 GW) from RES by 2022. Amongst RES, wind energy shows huge promise for the future, with almost 50% share in total grid-interactive RES capacity of India at present.
High volume power-electronics interfaced RES integration far from load-centers makes maintaining reliability, robustness and stability of grid operation more complex due to increased trans-national power exchanges, change in power system dynamics and transmission-system expansion constraints, which pushes the system closer to its limits. Moreover, stronger network linking poses a greater risk of wide area blackouts.
The impact of a blackout increases exponentially with the duration of its restoration, thus making restoration process planning highly critical. The 2012 blackout in India during which the northern, eastern and north-eastern grids collapsed on 30 & 31 July, affected the lives of about 300 million people and brought the rail-network, airports and businesses to a standstill, causing economic-disruption and chaos across northern India.
With the growing proportion of wind power in the grid and conventional generation being replaced, offshore wind power plants (OWPP) with state-of-the-art wind turbines (WTs) can address advanced requirements like black-start and power system restoration (PSR), as they can provide fast, high power environment-friendly black start capability to facilitate grid recovery.
Grid code requirements have been a major driver for the development of WT technology. In this paper, different grid-codes will be studied to systematically list out the technical requirements for generators to provide black-start/restoration services. Additionally, recent design notes on future black-start units to achieve restoration goals, and literature on the capabilities of WTs in the scope of black-start and islanded operation, will be reviewed. Finally, recommendations will be made to include WPP-specific modifications to grid codes or enhance the WT capabilities to facilitate black-start and power system restoration.
Share of RE in total installed capacity (350 GW) has reached over 21% and it is bound to go up as we move towards the ambitious target of 175 GW RE set by the Government of India (GoI). Climate change commitments and increased competitiveness of RE with conventional power indicates that RE will have a significant share in country’s installed capacity in long term as well.
Electricity markets have a vital role to play in integration of Renewable Energy (RE), particularly in view of positive RE growth outlook in medium to long term. The country today has a well-functioning Day Ahead Market (DAM) where substantial trades take place, providing price signals to both the demand and the supply side. However, beyond the DAM, other market forms like term-ahead and intra-day markets have not met with adequate success. Currently, the overall system relies largely on long term contracts and a scheduling mechanism where load serving entities and eligible customers schedule their own portfolio and also buy from the market on the margin. Imbalances are settled through the Unscheduled Interchange (UI)/ Deviation Settlement Mechanism (DSM) under an administered process from which India has begun to graduate to Ancillary Services (AS) markets.
The fast paced RE capacity addition necessitates relook at the current market design to mitigate the challenges emanating from ingress of variable and intermittent RE generation. Market design interventions require changes beginning with the current planning approaches, to signal how much RE can be economically and securely absorbed by the grid, along the need for network augmentation and operational changes. The Ancillary Services and Real Time markets must be robust to ensure effective mechanisms for handling and settlement of imbalances.
To layout a roadmap for electricity markets of the future, KPMG in India has undertaken a national workshop series, under the ‘Power Sector Reforms Programme’ supported by Department for International Development (DFID) and Ministry of Power (MoP). The series comprised consultation and exchange of ideas with a large number of stakeholders, market players, policy makers, regulators and experts and has led to identification of key challenges, priorities and actions for effecting changes in current market design.
The proposed paper intends to highlight the outcomes of the workshop series which aims to guide the policy makers in steering the market design changes, many of which will be critical for enabling large scale integration of RE. The paper will lay out the key challenges, market design options, international experience, stakeholder perspectives and imperatives for ushering in electricity markets of the future.
The increasing trend to integrate intermittent wind generation in restructured power systems introduces several operational issues including reserve management and market performance. Therefore, Very Short-Term Forecasting (VSTF) of wind speeds is highly emphasized to address these issues by accurate predication of Wind Farms’ (WFs) power outputs. State-of-the-art of VSTF typically provides a trade-off between machine learning and time series techniques. This paper provides an exhaustive study of statistical and machine learning VSTF models, i.e., linear regression, Autoregressive Integrated Moving Average (ARIMA), k-Nearest Neighbors (k-NN) and Artificial Neural Network (ANN). The performance of these models is evaluated by Root Mean Square Error (RMSE) and Mean Absolute Error (MAE). The study is carried out on the dataset of WF located at Jaisalmer, Rajasthan, India. The results obtained concludes that ANN outperform for VSTF of wind speed because of its ability to form complex non-linear systems for forecasting based on simple wind speed data. The ANN forecast accuracy is followed by linear regression, ARIMA and k-NN models.
The high wind energy potential sites are increasingly remote from the load centers which create problems in integrating wind power plants into power grids. One of the major issues is the short-circuit ratio (SSR) at the point of common coupling. A lower short-circuit ratio will lead to a weaker grid which in turn creates power system stability problems. The definition of a weak grid depends on short-circuit ratio values. In New Zealand, it is often noted that the definition of a weak grid, based on SSR, is different from that of standard values (of SSR) due to several reasons.
New Zealand’s grid is long and slender with arguably major generation at one end and load centers at the other side. Close to 80% of daily consumption of electricity is generated from renewables with 5-8% contributed by Wind generation. Wind farm locations in New Zealand share the same difficulties as shared by many nations in terms of remote locations, far away from load centers and wind variability. However, New Zealand wind farm capacity factor is close to 45% and maximum capacity of around 400 hours a year. Over 20 new wind farms have been consented for future with capacity close to 3GW.
This work shares our experience in connecting future wind farms to New Zealand grid and their effect on the weak grid concept. We will discuss the reasons for our definition of short-circuit ratio in New Zealand scenario and, in support, share some results of our simulations.
• Increase the flexibility and capacity of the existing power grid.
• Increase network flexibility for grid users at optimised OPEX, which allows for a larger share of RES and increased security of supply.
• Manage congestion within the grid without affecting system reliability.
• Defer CAPEX to build new lines by harnessing the hidden capacities of the existing system.
The integration of intrinsically variable R.E generations shall bring unpredictability in the form of sizeable fluctuations in power flows in transmission networks. It shall also further increase the need for grid reinforcement to guarantee security of supply. The power flows vary with time, seasonal variations as well as daily variations. The network additions to cater these power flows cannot be an economical solution always. Advanced transmission technologies must be tested, and the management of existing infrastructure must be improved. The new technologies like Dynamic line ratings and modular power flow control devices are being tested, implemented and are being successful in their operations in many parts of the world. This paper focus on the idea of integration of both Dynamic line rating and Power Flow controllers to enhance the flexibility of existing transmission infrastructure.