A fuzzy logic controller based mid-term load forecasting with renewable penetration in Assam, India

An accurate mid-term load forecasting (MTLF) tool is an essential part of power systems planning and sustainable development. In order to compensate the extra uncertainties, the power systems with high renewable penetration need even more accurate MTLF tool. The electric load demand is highly prejudiced by the thermal inertia due to the local climatic factors. Therefore, the accuracy of an MTLF method is highly dependent on the incorporated climatic factors. This paper proposes a fuzzy logic comptroller based MTLF method with renewable penetration. In order to achieve a higher degree of forecasting accuracy proposed method incorporated several climatic factors in the forecasting process. The study is done in Assam, a state of India and the proposed method is utilized to forecast the daily average load demand for one month. The forecasting accuracy of the proposed method is compared with one of most commonly used tool for MTLF called artificial neural network (ANN). The empirical results affirm the superiority of the proposed method over the ANN

Data Driven Building Electricity Consumption Model Using Support Vector Regression

Every building has certain electricity consumption patterns that depend on its usage. Building electricity budget planning requires a consumption forecast to determine the baseline electricity load and to support energy management decisions. In this study, an algorithm to model building electricity consumption was developed. The algorithm is based on the support vector regression (SVR) method. Data of electricity consumption from the past five years from a selected building object in ITB campus were used. The dataset unexpectedly exhibited a large number of anomalous points. Therefore, a tolerance limit of hourly average energy consumption was defined to obtain good quality training data. Various tolerance limits were investigated, that is 15% (Type 1), 30% (Type 2), and 0% (Type 0). The optimal model was selected based on the criteria of mean absolute percentage error (MAPE) < 20% and root mean square error (RMSE) < 10 kWh. Type 1 data was selected based on its performance compared to the other two. In a real implementation, the model yielded a MAPE value of 14.79% and an RMSE value of 7.48 kWh when predicting weekly electricity consumption. Therefore, the Type 1 data-based model could satisfactorily forecast building electricity consumption

A SVM framework for fault detection of the braking system in a high speed train

In April 2015, the number of operating High Speed Trains (HSTs) in the world has reached 3603. An efficient, effective and very reliable braking system is evidently very critical for trains running at a speed around 300 km/h. Failure of a highly reliable braking system is a rare event and, consequently, informative recorded data on fault conditions are scarce. This renders the fault detection problem a classification problem with highly unbalanced data. In this paper, a Support Vector Machine (SVM) framework, including feature selection, feature vector selection, model construction and decision boundary optimization, is proposed for tackling this problem. Feature vector selection can largely reduce the data size and, thus, the computational burden. The constructed model is a modified version of the least square SVM, in which a higher cost is assigned to the error of classification of faulty conditions than the error of classification of normal conditions. The proposed framework is successfully validated on a number of public unbalanced datasets. Then, it is applied for the fault detection of braking systems in HST: in comparison with several SVM approaches for unbalanced datasets, the proposed framework gives better results

Integrating physical and data-driven system frequency response modelling for wind-PV-thermal power systems

This paper presents an integrated system frequency response (SFR) modelling method for wind-PV-thermal power systems (WPTPSs) by combining both physical model-based and data-driven modelling methods. The SFR physical model is built and simplified by the balanced truncation (BT) method. Based on the physical model, an improved radial basis function neural networks (RBFNNs) is then employed to establish an off-line SFR model using source data. Following the transfer learning principle, the transferred data from the source data set is determined by the maximum mean discrepancy (MMD) criterion. The RBFNN-based SFR model is then fine-tuned using both the transferred source data and target data. Finally, the fine-tuned RBFNNs is applied to investigate real-time SFR of WPTPSs. Simulation results confirm the effectiveness of the proposed SFR modelling strategy with an illustrative WPTPS

Load forecast on a Micro Grid level through Machine Learning algorithms

As Micro Redes constituem um sector em crescimento da indústria energética, representando uma mudança de paradigma, desde as remotas centrais de geração até à produção mais localizada e distribuída. A capacidade de isolamento das principais redes elétricas e atuar de forma independente tornam as Micro Redes em sistemas resilientes, capazes de conduzir operações flexíveis em paralelo com a prestação de serviços que tornam a rede mais competitiva. Como tal, as Micro Redes fornecem energia limpa eficiente de baixo custo, aprimoram a coordenação dos ativos e melhoram a operação e estabilidade da rede regional de eletricidade, através da capacidade de resposta dinâmica aos recursos energéticos. Para isso, necessitam de uma coordenação de gestão inteligente que equilibre todas as tecnologias ao seu dispor. Daqui surge a necessidade de recorrer a modelos de previsão de carga e de produção robustos e de confiança, que interligam a alocação dos recursos da rede perante as necessidades emergentes. Sendo assim, foi desenvolvida a metodologia HALOFMI, que tem como principal objetivo a criação de um modelo de previsão de carga para 24 horas. A metodologia desenvolvida é constituída, numa primeira fase, por uma abordagem híbrida de multinível para a criação e escolha de atributos, que alimenta uma rede neuronal (Multi-Layer Perceptron) sujeita a um ajuste de híper-parâmetros. Posto isto, numa segunda fase são testados dois modos de aplicação e gestão de dados para a Micro Rede. A metodologia desenvolvida é aplicada em dois casos de estudo: o primeiro é composto por perfis de carga agregados correspondentes a dados de clientes em Baixa Tensão Normal e de Unidades de Produção e Autoconsumo (UPAC). Este caso de estudo apresenta-se como um perfil de carga elétrica regular e com contornos muito suaves. O segundo caso de estudo diz respeito a uma ilha turística e representa um perfil irregular de carga, com variações bruscas e difíceis de prever e apresenta um desafio maior em termos de previsão a 24-horas A partir dos resultados obtidos, é avaliado o impacto da integração de uma seleção recursiva inteligente de atributos, seguido por uma viabilização do processo de redução da dimensão de dados para o operador da Micro Rede, e por fim uma comparação de estimadores usados no modelo de previsão, através de medidores de erros na performance do algoritmo.Micro Grids constitute a growing sector of the energetic industry, representing a paradigm shift from the central power generation plans to a more distributed generation. The capacity to work isolated from the main electric grid make the MG resilient system, capable of conducting flexible operations while providing services that make the network more competitive. Additionally, Micro Grids supply clean and efficient low-cost energy, enhance the flexible assets coordination and improve the operation and stability of the of the local electric grid, through the capability of providing a dynamic response to the energetic resources. For that, it is required an intelligent coordination which balances all the available technologies. With this, rises the need to integrate accurate and robust load and production forecasting models into the MG management platform, thus allowing a more precise coordination of the flexible resource according to the emerging demand needs. For these reasons, the HALOFMI methodology was developed, which focus on the creation of a precise 24-hour load forecast model. This methodology includes firstly, a hybrid multi-level approach for the creation and selection of features. Then, these inputs are fed to a Neural Network (Multi-Layer Perceptron) with hyper-parameters tuning. In a second phase, two ways of data operation are compared and assessed, which results in the viability of the network operating with a reduced number of training days without compromising the model's performance. Such process is attained through a sliding window application. Furthermore, the developed methodology is applied in two case studies, both with 15-minute timesteps: the first one is composed by aggregated load profiles of Standard Low Voltage clients, including production and self-consumption units. This case study presents regular and very smooth load profile curves. The second case study concerns a touristic island and represents an irregular load curve with high granularity with abrupt variations. From the attained results, it is evaluated the impact of integrating a recursive intelligent feature selection routine, followed by an assessment on the sliding window application and at last, a comparison on the errors coming from different estimators for the model, through several well-defined performance metrics

A Novel RBF Training Algorithm for Short-Term Electric Load Forecasting and Comparative Studies

Because of their excellent scheduling capabilities, artificial neural networks (ANNs) are becoming popular in short-term electric power system forecasting, which is essential for ensuring both efficient and reliable operations and full exploitation of electrical energy trading as well. For such a reason, this paper investigates the effectiveness of some of the newest designed algorithms in machine learning to train typical radial basis function (RBF) networks for 24-h electric load forecasting: support vector regression (SVR), extreme learning machines (ELMs), decay RBF neural networks (DRNNs), improves second order, and error correction, drawing some conclusions useful for practical implementations

Forecasting methods in energy planning models

Energy planning models (EPMs) play an indispensable role in policy formulation and energy sector development. The forecasting of energy demand and supply is at the heart of an EPM. Different forecasting methods, from statistical to machine learning have been applied in the past. The selection of a forecasting method is mostly based on data availability and the objectives of the tool and planning exercise. We present a systematic and critical review of forecasting methods used in 483 EPMs. The methods were analyzed for forecasting accuracy; applicability for temporal and spatial predictions; and relevance to planning and policy objectives. Fifty different forecasting methods have been identified. Artificial neural network (ANN) is the most widely used method, which is applied in 40% of the reviewed EPMs. The other popular methods, in descending order, are: support vector machine (SVM), autoregressive integrated moving average (ARIMA), fuzzy logic (FL), linear regression (LR), genetic algorithm (GA), particle swarm optimization (PSO), grey prediction (GM) and autoregressive moving average (ARMA). In terms of accuracy, computational intelligence (CI) methods demonstrate better performance than that of the statistical ones, in particular for parameters with greater variability in the source data. However, hybrid methods yield better accuracy than that of the stand-alone ones. Statistical methods are useful for only short and medium range, while CI methods are preferable for all temporal forecasting ranges (short, medium and long). Based on objective, most EPMs focused on energy demand and load forecasting. In terms geographical coverage, the highest number of EPMs were developed on China. However, collectively, more models were established for the developed countries than the developing ones. Findings would benefit researchers and professionals in gaining an appreciation of the forecasting methods, and enable them to select appropriate method(s) to meet their needs

Coordinated Voltage and Reactive Power Control for Renewable Dominant Smart Distribution Systems

Driven by their economic and environmental advantages, smart grids promote the deployment of active components, including renewable energy sources (RESs), energy storage systems (ESSs), and electric vehicles (EVs), for sustainability and environmental benefits. As a result of smart grid technologies and the amount of data collected by smart meters, better operation and control schemes can be developed to allow for cleaner energy with high efficiency, and without breaching network operating constraints. Power distribution networks may face some operational and control challenges as the integration of intermittent energy sources (wind and PV power systems) increases. Some of these challenges include voltage rise and fluctuation, reverse power flow, and the malfunction of conventional Volt/Var control devices. Depending on their location, RESs may introduce two issues related to the Volt/Var control problem, the first of which is that the severity of loading variations will be greater than the case without RESs. The second occurs when the RES is connected between the load center and any regulating devices. The power in-feed from the intermittent RESs may not only mislead the regulator’s control circuit, resulting in unfavorable voltage, but may also enforce the regulator taps to operate randomly following bus voltage variations. This thesis investigates and presents a methodology for the Volt/Var control problem in Smart Distribution Grids (SDGs) under the high penetration and fluctuation of RESs. The research involves the application of predictive control actions to optimally set Volt/Var control devices before the predicted voltage violation takes place. The main objective of this controller is to manage and control the operation of Volt/Var devices in an optimal way that improves the voltage profile along the feeders, reduces real power losses and minimizes the number of Volt/Var device taps and/or switching movements under all loading conditions and for high penetration RESs. This thesis first presents a very Short-Term Stacking Ensemble (STSE) forecasting model for solar PV and wind power outputs that is developed to predict the generated power for intervals of 15 minutes. The proposed model combines heterogeneous machine learning algorithms composed of three well-established models: Support Vector Regression (SVR); Radial Basis Function Neural Network (RBFNN); and Random Forest (RF) heuristically via SVR. The STSE model aims to minimize the prediction error associated with renewable resources when used in the real-time operation of power distribution networks. Secondly, a day-ahead Predictive Volt/Var Control (PVVC) model is developed to find the optimal coordination between Volt/Var control devices under the high penetration and power variations of RESs. The objective of the PVVC model is defined as simultaneous minimization of voltage deviation at each bus, power losses, operating cycle of regulation equipment, and RES curtailment. The benefit of using smart inverter interface RESs with the capability of injective/absorbing reactive power is examined and applied as ancillary services for voltage support. Thirdly, a Sequential Predictive Control (SPC) Strategy for smart grids is developed. The model uses the past and currently available data to forecast demand and RES outputs for intervals of 15 minutes, with real-time updating mechanisms. It then schedules the settings and operations of Volt/Var control devices by solving the Volt/Var control problem in a rolling horizon optimization framework. Because the optimization must be solved in a short interval with a global solution, a solution methodology for linearizing the nonlinear optimization problem is adapted. The original control problem, which is a Mixed-Integer Nonlinear Programming (MINLP) optimization problem, is transformed into a Mixed Integer Second Order Conic Programming (MISOCP) problem that guarantees a global solution through convexity and remarkably reduces the computational burden. Case studies carried out to compare the proposed model against state-of-the-art models provides evidence for the proposed model’s effectiveness. Results indicate that the SPC is capable of accurately solving the control problem within small time slots. The proposed models aim to efficiently operate SDGs at a high penetration level of RES for a day-ahead, as well as in real-time, depending on the preference of network operators. The primary purpose is to minimize operating costs while increasing the efficiency and lifespan of Volt/Var control devices

Contributions to industrial process condition forecasting applied to copper rod manufacturing process

Ensuring reliability and robustness of operation is one of the main concerns in industrial anufacturing processes , dueto the ever-increasing demand for improvements over the cost and quality ofthe processes outcome. In this regard , a deviation from the nominal operating behaviours implies a divergence from the optimal condition specification, anda misalignment from the nominal product quality, causing a critica! loss of potential earnings . lndeed, since a decade ago, the industrial sector has been carried out a significant effortAsegurar la fiabilidad y la robustez es uno de los principales objetivos en la monitorización de los procesos industriales, ya que estos cada vez se encuentran sometidos a demandas de producción más elevadas a la vez que se deben bajar costes de fabricación manteniendo la calidad del producto final. En este sentido, una desviación de la operación del proceso implica una divergencia de los parámetros óptimos preestablecidos, lo que conlleva a una desviación respecto la calidad nominal del producto final, causando así un rechazo de dicho producto y una perdida en costes para la empresa. De hecho, tanto es así, que desde hace más de una década el sector industrial ha dedicado un esfuerzo considerable a la implantación de metodologías de monitorización inteligente. Dichos métodos son capaces extraer información respecto a la condición de las diferentes maquinarias y procesos involucrados en el proceso de fabricación. No obstante, esta información extraída corresponde al estado actual del proceso. Por lo que obtener información respecto a la condición futura de dicho proceso representa una mejora significativa para poder ganar tiempo de respuesta para la detección y corrección de desviaciones en la operación de dicho proceso. Por lo tanto, la combinación del conocimiento futuro del comportamiento del proceso con la consecuente evaluación de la condición del mismo, es un objetivo a cumplir para la definición de las nuevas generaciones de sistemas de monitorización de procesos industriales. En este sentido, la presente tesis tiene como objetivo la propuesta de metodologías para evaluar la condición, actual y futura, de procesos industriales. Dicha metodología debe estimar la condición de forma fiable y con una alta resolución. Por lo tanto, en esta tesis se pretende extraer la información de la condición futura a partir de un modelado, basado en series temporales, de las señales críticas del proceso, para después, en base a enfoques no lineales de preservación de la topología, fusionar dichas señales proyectadas a futuro para conocer la condición. El rendimiento y la bondad de las metodologías propuestas en la tesis han sido validadas mediante su aplicación en un proceso industrial real, concretamente, con datos de una planta de fabricación de alambrón de cobre