Minimización de pérdidas en sistemas de transmisión HVDC multi-terminal usando la técnica de optimización MVMO

La creciente inserción de generación principalmente renovable a los sistemas de potencia interconectados hace necesario que sistemas de transmisión HVDC sean considerados como posibilidad de transporte de energía eléctrica. Estos sistemas tienen una operación más complicada en relación a sistemas AC tradicionales; pero por otra parte tiene un mejor control de voltaje y potencia. Es así que en este trabajo se realiza la minimización de pérdidas en un sistema de transmisión HVDC, tomando como elemento de control los voltajes de las estaciones convertidoras de una red en DC. Para esta optimización se emplea el método MVMO (Optimización por Mapeo de Media Varianza), y la red HVDC de prueba es la denominada CIGRE B4 DC. Tanto el sistema de prueba como el método de optimización son implementados en el software DIgSILENT PowerFactory, encontrando para varios casos resultados favorables, con mínimas pérdidas, representando esto para el sistema una mejor condición operativa y económica.The increasing insertion of mainly renewable generation to interconnected power systems makes it necessary for HVDC transmission systems to be considered as a possibility of transporting electrical energy. These systems have a more complicated operation in relation to traditional AC systems; but on the other hand it has better voltage and power control. Thus, in this work the minimization of losses is performed in an HVDC transmission system, taking as control element the voltages of the converting stations of a DC network. For this optimization the MVMO method (Optimization by Medium Variance Mapping) is used, and the test HVDC network is called CIGRE B4 DC. Both the test system and the optimization method are implemented in the DIgSILENT PowerFactory software, finding for several cases favorable results, with minimal losses, representing for the system a better operational and economic condition

Analysis on the voltage stability on transmission network with PV interconnection

Voltage stability means the ability of the power system network to maintain steady-state voltage value at all buses in the system under normal condition and after being subjected to a disturbance. This research highlights the effect of solar photovoltaic (PV) as the subject of disturbance to the network system as this kind of energy source has emerged towards higher level of integration into the national grid. High penetration of solar PV into the grid may cause several issues of stability and security to the system particularly effecting the normal voltage and line overloading. This research is focused on the simulation of power flow to study the transmission network behavior with and without the solar PV interconnection. To accomplish the research objectives, the network system will be modelled in a software known as Power System Simulator for Engineering (PSSE). The simulation result will be discussed and analyzed using Voltage Stability Indices (VSI) to prove and strengthen the theory behind the literature review

Simulación de la influencia del STATCOM en las pérdidas del sistema de potencia

The supply of growing electricity demand is possible through continuous technological advances and the expansion of national and international electrical systems. This scenario could introduce voltage drops and consequent changes in the reactive power flow throughout the electrical network. In order to control these problems, various strategies have been developed as a solution to improve the transport and distribution of electrical energy. One of them is the Flexible Alternating Current Transmission System (FACTS), and more specifically the STATic synchronous COMpensator (STATCOM). This paper investigates the influence and effectiveness of STATCOM to mitigate the losses in the transmission lines and its impacts on bus voltage drops. The simulations are performed using the software DIgSILENT PowerFactory and the results showed that STATCOM reduces the power system losses in an interval of 23.86% until 32.86%, and in addition, the STATCOM decreases the annual energy cost by 7.82% in the implemented test case.El abastecimiento de la creciente demanda eléctrica es posible a través de los continuos avances tecnológicos y la expansión de los sistemas eléctricos nacionales e internacionales. Este escenario podría introducir caídas de tensión y los consiguientes cambios en el flujo de potencia reactiva en toda la red eléctrica. Para controlar estos problemas se han desarrollado diversas estrategias como solución para mejorar el transporte y distribución de energía eléctrica. Uno de ellos es el Sistema Flexible de Transmisión de Corriente Alterna (FACTS), y más concretamente el STATic synchronous COMpensator (STATCOM). Este artículo investiga la influencia y efectividad del STATCOM para mitigar las pérdidas en las líneas de transmisión y sus impactos en las caídas de tensión de las barras. Las simulaciones se realizan utilizando el software DIgSILENT PowerFactory y los resultados mostraron que el STATCOM reduce las pérdidas del sistema de potencia en un intervalo de 23,86% hasta 32,86%, y además, el STATCOM disminuye el costo anual de energía en 7,82% en el caso de prueba implementado.

Load-ability Analysis during Contingency with Unified Power Flow Controller Using Grey Wolf Optimization Technique

Voltage stability enhancement with optimal placement of a unified power flow controller considering load-ability analysis is investigated in this paper. It is essential, because when voltage instability is left unattended, it leads to voltage collapse and, consequently, in a partial or total blackout of the whole network resulting from cascading effect. The optimization process is achieved by increasing the percentage load demand index to the maximum load-ability and under single contingency. This method will be of great benefits to bulk dispatcher of power to plan ahead of how to wheel and deliver power to the end-users during both normal and contingency conditions at the least cost and time. A grey wolf optimization technique is utilised to find the optimal location and sizing of UPFC on the network. The line’s voltage stability and load margin are then evaluated with and without UPFC under different loading conditions using optimal power flow technique. The approach’s effectiveness is carried out on 31-bus, 330kV Nigeria National Grid (NNG) based on two scenarios: load-ability analysis under maximum loading of the network and load-ability analysis under single contingency. The results show that power can be transmitted to meet the growing energy demand over an existing network during normal and contingency conditions without violating voltage stability by making use of the proposed method in this pape

Enhancement of Voltage Stability with Unified Power Flow Controller Considering Loadability Analysis

Voltage stability is an important issue in planning and operation of electric power system during both normal and under contingency conditions. This paper presents line voltage stability index (LVSI) for transmission lines voltage stability assessment and evaluation. The system stability under maximum loading and contingency conditions are analyzed using optimal power flow analysis. FACTS device is considered for a real-time control and a dynamic reactive power compensation of the system. Voltage source-based power injection model of unified power flow controller (UPFC) is used for the minimization of voltage deviation and losses on the network. Optimal location and sizing of UPFC is carried out using grey wolf optimization (GWO) technique in order to identify an optimal location where the FACTS device will be installed. UPFC device has proven to increase the line transmittable power, controls the voltage magnitude at the buses as well as enhancing the stability and security of the power system. The various conditions and scenarios used to test the efficacy of this model for system stability and security under contingency conditions are demonstrated on standard IEEE 14-bus test system

Improvement of voltage stability and loadability of power system employing the placement of unified power flow controller using artificial neural network

This paper proposes a voltage stability and loadability improvement model of power systems by incorporating the optimal placement of flexible alternating current transmission systems (FACTS) using an artificial neural network (ANN) called OPFANN. The key aspect of this model is to identify the weakest lines which having the most probability of voltage collapse utilized for placing FACTS devices. As installing a new power system network with rapidly increasing power demand cannot be possible, the operator usually operates the power system close to the stability limit. In this regard, continuous monitoring and improvement of system voltage stability and loadability of the existing system are vital issues for energy management systems nowadays. However, the proposed OPFANN introduces a more straightforward and faster scheme for voltage stability monitoring systems using ANN. Intelligent and reliable data samples have been designed to train the ANN based on two-line voltage stability indices (LVSI) techniques. Compared with other works, OPFANN effectively improves voltage stability and loadability at the load point by installing the unified power flow controller (UPFC) FACTS devices to the weakest lines. OPFANN can provide information on voltage collapse points using ANN and reduce the further computational cost of LVSI. Finally, OPFANN ensures faster and more secure operation of the power system

Control de voltaje en sistemas eléctricos de potencia usando transformadores con taps.

Para la operación normal de un sistema eléctrico de potencia se analiza y controla diferentes variables eléctricas, siendo una de las más relevantes el nivel de voltaje en los nodos del sistema, en tal sentido un inadecuado monitoreo y control del voltaje pueden llevar al sistema eléctrico de potencia a un colapso, lo que ha ocasionado apagones masivos en diferentes países a nivel mundial. Por lo expuesto, el presente trabajo se enfoca en realizar el control de voltaje mediante el uso de los taps de los transformadores de potencia. Para el efecto se ha elaborado el modelo matemático del método de Newton- Raphson modificado, que permite considerar el efecto de los taps en los transformadores y su implicación en el control del voltaje en las barras del sistema, el cual es simulado en Matlab. A fin de validar la modelación propuesta, ésta es aplicada al sistema IEEE de 14 barras sujeto a distintas condiciones operativas, permitiendo de esta manera establecer los aspectos concluyentes en relación al aporte de la conservación de niveles de voltaje aceptables resultado de la representación de los taps de los transformadores de potencia.For a normal operation of an electric power system it is required to analyze and control different electrical variables being one of the most relevant the voltage in the nodes of the power system, in this sense an inadequate monitoring and voltage control of the power system could lead to a collapse of the power system something that has already happen in various countries and at a wide-world level. Therefore, this paper focuses on performing of voltage control by using the taps of the power transformers. For this purpose, a mathematical model of the modified Newton-Raphson method has been developed, which allows considering the effect of the taps on the transformers and their involvement in the control of the voltage in the bars of the system, which is simulated in Matlab. In order to validate the proposed modeling, it is applied to the IEEEE system of 14 buses subject to different operating conditions, thus allowing to establish the conclusive aspects in relation to the contribution of the conservation of acceptable voltage levels resulting from the representation of the taps of power transformers

Review of Voltage Stability Indices

Voltage stability indices (VSIs) are very vital to voltage stability assessment; they have several areas of application such as distributed generation (DG) placement and sizing, detection of the critical regions, lines, and buses and contingency ranking and planning. These indices can be used to activate countermeasures against voltage instability. This article examines voltage stability indices with particular focus on line VSIs, and it highlights the classification, accuracy of VSIs, and enumerates for some selected line VSIs drawbacks and advantages as seen in literature

Power System Loading Margin Enhancement by Optimal STATCOM Integration:a case study

Safe and secure network operation with acceptable voltage level has become a challenging task for utilities requiring corrective measures to be implemented. Network upgrades using Flexible Alternating Current Transmission System devices are being considered to serve this purpose. To this end, static loading margin enhancement by optimal static synchronous compensator (STATCOM) allocation to enhance the power transfer capability with minimal voltage variation is presented. Maximum loadability is formulated as an optimization problem, subjected to voltage and small-signal stability constraints. Stability indices are presented and incorporated with the optimization problem to ensure secure operation under maximum loading. The scheme is executed with the IEEE system and an Indian utility network. Improved voltage regulation with different loading condition was achieved for both test networks, with the service rendered by the optimally placed STATCOM. Moreover, it facilitates an additional 50% capacity release in both test systems for hosting the active power and loads

Simulación de la Influencia del STATCOM en las Pérdidas del Sistema de Potencia

The supply of growing electricity demand is possible through continuous technological advances and the expansion of national and international electrical systems. This scenario could introduce voltage drops and consequent changes in the reactive power flow throughout the electrical network. In order to control these problems, various strategies have been developed as a solution to improve the transport and distribution of electrical energy. One of them is the Flexible Alternating Current Transmission System (FACTS), and more specifically the STATic synchronous COMpensator (STATCOM). This paper investigates the influence and effectiveness of STATCOM to mitigate the losses in the transmission lines and its impacts on bus voltage drops. The simulations are performed using the software DIgSILENT PowerFactory and the results showed that STATCOM reduces the power system losses in an interval of 23.86% until 32.86%, and in addition, the STATCOM decreases the annual energy cost by 7.82% in the implemented test case.El abastecimiento de la creciente demanda eléctrica es posible a través de los continuos avances tecnológicos y la expansión de los sistemas eléctricos nacionales e internacionales. Este escenario podría introducir caídas de tensión y los consiguientes cambios en el flujo de potencia reactiva en toda la red eléctrica. Para controlar estos problemas se han desarrollado diversas estrategias como solución para mejorar el transporte y distribución de energía eléctrica. Uno de ellos es el Sistema Flexible de Transmisión de Corriente Alterna (FACTS), y más concretamente el STATic synchronous COMpensator (STATCOM). Este artículo investiga la influencia y efectividad del STATCOM para mitigar las pérdidas en las líneas de transmisión y sus impactos en las caídas de tensión de las barras. Las simulaciones se realizan utilizando el software DIgSILENT PowerFactory y los resultados mostraron que el STATCOM reduce las pérdidas del sistema de potencia en un intervalo de 23,86% hasta 32,86%, y además, el STATCOM disminuye el costo anual de energía en 7,82% en el caso de prueba implementado.