Transmissionmanagementforcongestedpowersystem:Areviewof concepts,technicalchallengesanddevelopmentofanewmethodology

Transmissionnetworkshavesomeconstraintsthatshouldbeaddressedinordertoensuresufficient\ud control tomaintainthesecuritylevelofapowersystemwhilemaximisingmarketefficiency.Themost\ud obviousdrawbackoftransmissionconstraintsisacongestionproblemthatbecomesanobstacleto\ud perfect competitionamongthemarketparticipantssinceitcaninfluence spotmarketpricing.Asthe\ud power flow violatestransmissionconstraints,redispatchinggeneratingunitsisrequiredandthiswill\ud cause thepriceateverynodetovary.Thismanuscriptpresentsconcepts,technicalchallengesand\ud methodology forinvestigatinganalternativesolutiontotheredispatchmechanismandthenformulates\ud LMP schemeusinganoptimisationtechniquethatmaywellcontrolcongestionasthemainissue.The\ud LMP schemearevariedandimprovedtotakeintoaccounttheenergyprice,congestionrevenue,costof\ud losses, aswellasthetransmissionusagetariffbyutilisingshiftfactor-basedoptimalpower flow\ud (SF-OPF), whichisderivedfromthewell-knownDCoptimalpower flow(DC-OPF)mode

Perencanaan Pelepasan Beban Dengan Analisis Eigenvalue dan Eigenvector

Sejak tahun 1920-an, kestabilan sistem tenaga listrik telah diidentifikasi sebagai persyaratan utama untuk pengoperasian sistem tenaga listrik yang aman dan andal. Ketidakstabilan tegangan dapat membawa seluruh sistem jaringan ke keadaan penurunan tegangan yang signifikan, oleh karena itu tindakan pencegahan diperlukan. Salah satu cara yang ekonomis untuk mencegah jatuh tegangan atau voltage collapse adalah pelepasan beban atau under voltage load shedding (UVLS), dimana pengurangan beban kecil antara 5% dan 10% dari total beban sistem dapat menjaga kestabilan sistem. Pelepasan beban akibat tegangan rendah atau under voltage memegang peranan penting dalam sistem kendali tenaga listrik ketika sistem mengalami gangguan yang besar. Pengurangan beban telah digunakan sejak lama sebagai alternatif terakhir untuk mencegah kegagalan sistem tenaga utama yang diaktifkan oleh relai under-frequency atau relai under-voltage. Makalah ini mengusulkan metode berdasarkan analisis modal untuk pelepasan beban yang menggunakan eigenvalue dan eigenvector kemudian menghitung faktor partisipasi bus untuk menentukan lokasi pelepasan beban. Penelitian ini mengkaji keefektifan faktor partisipasi dalam menentukan lokasi pelepasan beban. Kata Kunci: analisis modal, eigenvalue, faktor partisipasi, kestabilan tegangan, pelepasan beban

Analytical Method for Reactive Power Compensators Allocation

This paper presents a novel analytical methodology to determine location for reactive power devices placement in power systems. The proposed method modifies modal analysis technique and develops new formulation to compute the Reactive Contribution Factor (RCF) of each load buses based on the inversed reduced Jacobian matrix. The objective of this research is to achieve the most stable condition as well as to minimize network losses. The proposed method is implemented at the modified IEEE 30-bus Reliability Test System (RTS) and compared with different placement. This work compares the voltage profile, eigenvalue and network losses to assess the method. The simulation results show the proposed method can provide a solution to the ideal shunt compensator placement to improve the system’s voltage stability and minimizing losses

Studi Penempatan Distributed Generation Optimal Mempertimbangkan Kenaikan Beban

The distribution network is strongly influenced by an increase in the demand for electrical energy, which can cause increased power losses in the system and a decrease in bus voltage in the system. To overcome the problem of increasing power loss in the system and reducing voltage, then one alternative that can be done is the use of Distributed Generation (DG) in the distribution system. To get the best power loss reductionpossible, the determination of the location and capacity of DG must be carried out optimally by using an optimization method. In this study, the optimization method used is the Flower Pollination Algorithm (FPA) method. This research was tested on a 33 bus radial distribution system with IEEE standards by paying attention to the increase in load on the systemJaringan distribusi sangat dipengaruhi oleh adanya peningkatan permintaan energi listrik, yang dapat menyebabkan bertambahnya rugi-rugi daya pada sistem serta penurunan tegangan bus pada sistem. Untuk mengatasi permasalahan peningkatan rugi daya pada sistem dan penurunan tegangan, maka salah satu alternatif yang bisa dilakukan yaitu penggunaan Distributed Generation (DG) pada sistem distribusi. Untuk mendapatkan penurunan rugi daya sebaikmungkin maka penentuan lokasi dan kapasitas DG harus dilakukan dengan optimal dengan menggunakan suatu metode optimasi. Dalam penelitian ini, metode optimasi yang digunakan adalah metode Flower Pollination Algorithm (FPA). Penelitian ini diujikan pada sistem distribusi radial 33 bus dengan standar IEEE dengan memperhatikan kenaikan beban pada siste

Penempatan Distributed Generation Optimal Mempertimbangkan Rekonfigurasi Jaringan

An increase in electrical energy can cause an increase in power losses and a decrease in voltage in the system. One of the efforts made to reduce power losses that occur in the distribution network is by placing Distributed Generation (DG). There have been many studies related to optimal DG placement and one of the artificial intelligence methods used to solve this problem is the flower pollination algorithm method. In addition, network reconfiguration can improve power quality by reducing power losses, increasing reliability, voltage stability and load balance. This study aims to determine the optimal position and capacity of DG and determine the impact or effect of network reconfiguration on DG installation solutions in radial distribution systems.Peningkatan energi listrik dapat menyebabkan adanya peningkatan rugi-rugi daya dan penurunan tegangan pada sistem. Salah satu upaya yang dilakukan untuk mengurangi rugi-rugi daya yang terjadi di jaringan distribusi yaitu dengan penempatanDistributed Generation (DG). Telah banyak penelitian terkait penempatan DG optimal dan salah satu metode kecerdasan buatan yang digunakan untuk menyelesaikan permasalahan ini adalah metode algoritma penyerbukan bunga. Selain itu, rekonfigurasi jaringan dapat meningkatkan kualitas daya dengan cara mengurangi rugi-rugi daya, meningkatkan keandalan,kestabilan tegangan dan keseimbangan pembebanan. Penelitian ini bertujuan untuk menentukan posisi dan kapasitas DG optimal serta mengetahui dampak atau pengaruh dengan adanya rekonfigurasi jaringan terhadap solusi pemasangan DG pada sistem distribusi radial

Optimasi Penentuan Letak Pembangkit Tersebar (Distributed Generation) Pada Sistem Distribusi Radial Dengan Adanya Kapasitor

Pembangkit terdistribusi atau Distributed  Generation (DG)  adalah pembangkit berkapasitas lebih kecil dibandingkan pembangkit listrik utama. DG   terinjeksi langsung  pada  sistem distribusi  dan terletak di dekat pusat-pusat beban.  Pemasangan  DG  dirancang  untuk  memperoleh rugi-rugi daya minimum dan profil tegangan berada pada batasannya. Metode optimasi yang digunakan dalam penelitian ini adalah Algoritma Penyerbukan Bunga atau Flower Pollination Algorithm (FPA). Penelitian ini diujikan pada SDR 33 bus dengan standar IEEE yang memperhatikan adanya kapasitor pada sistem.  Hasil  analisis   dari penelitian ini diperoleh bahwa pemasangan multi DG dan dengan ukuran kapasitor yang lebih besar di SDR lebih optimal dalam memperoleh rugi-rugi daya minimum dan   profil tegangan berada pada batasannya dengan lokasi DG yang sama

Advanced computational methods for system voltage stability enhancement

Keywords: \ud under voltage load shedding, \ud voltage stability analysis, \ud modal analysis, \ud continuation power flow, \ud trajectory sensitivity analysis, \ud distributed generations, \ud doubly fed induction generator, \ud dynamic load modelling, \ud eigenvalue, \ud eigenvectorPower system stability has been recognised as a crucial requirement for the reliable and secure operation of electricity power systems for almost one century. Because of this, power engineers and researchers have developed various techniques to manage instability and to maintain power system stability and reliability. Especially in modern power systems, problems occur in the form of voltage instability, frequency instability and inter-area oscillations, particularly cascading failures leading to system blackout. Voltage stability analysis plays a vital role in predicting potential voltage instability. During the planning and operation of a power system, voltage problems have become a great concern, because a considerably large number of failures are believed to have been caused by voltage instability. In recent years, much research has been undertaken to investigate this phenomenon. \ud This thesis explores various techniques for power system stability enhancement focusing on voltage stability. There are two main areas of investigation in this project. Firstly, this dissertation proposes a new technique for the optimal placement of distributed generations (DGs) at the distribution network to improve voltage stability. Secondly, this thesis develops a new method for under voltage load shedding (UVLS) to provide protection for unusual disturbances that are outside the planning and operating criteria when a power system is being perturbed.\ud The integration of distributed generations at the distribution system can improve power system reliability and voltage stability. However, these benefits depend on the size and location of the distributed generations. Therefore, it is important to determine the proper location of DGs in order to maximise their benefits. Currently, the optimal allocations of DG units are one of the major challenges for power system engineers. How to plan DGs to best utilise renewable energy sources while maintaining system security is an important problem. This project investigates the optimal placement of multiple DG units to obtain the most stable system and the highest network loss reduction. The proposed method in this project is based on two advanced voltage stability analysis methods: the reformulated Voltage-Active Power Modal Analysis (VPMA) and the Continuation Power Flow (CPF) methodologies or combined VPMA-CPF method. In this work, the initial modal analysis is modified to evaluate the system voltage stability by considering the incremental relationship between V and P instead of between V and Q. The VPMA method involves eigenvalue techniques and the associated eigenvectors of the reduced Jacobian matrix. The eigenvectors of the reduced Jacobian matrix are calculated to determine the Voltage-Active Power Modal Participation Factor (VPMPF). On the other hand, the CPF method employs the predictor-corrector steps scheme to achieve a solution path and then calculates the Tangent Vector Sensitivity Index (TVSI). Both the VPMPF and TVSI provide an indication of the weakest bus in the system. Furthermore, an objective function based on loss reduction and eigenvalue is formulated to determine the most appropriate bus location for DG placement. \ud Power systems are subjected to variety of disturbances. Failure to protect the system may lead to equipment damage and structural changes that trigger cascading failures and blackouts. One of the mitigation actions for voltage instability is under voltage load shedding (UVLS). Research and experience have provided evidence that UVLS is a powerful counter-measure action to preclude voltage instability. This research develops an under voltage load shedding scheme based on dynamic voltage stability analysis using trajectory sensitivity to alleviate voltage collapse in a large heavily stressed power system. This works presents a method to determine the minimum amount and the most appropriate location of load shedding considering dynamic load motor. The power system investigated in this study has quite a large amount of air conditioning and water pumping. The system load is modelled in detail as a composite load model that consists of static and dynamic motor loads. This work investigates the impact of composite load after a large disturbance causing the loss of a transmission line. The proposed technique used in this research involves an iterative algorithm based on trajectory sensitivity analysis to solve the load shedding problem. The amount of load to be shed for each iteration is set at a low level; approximately 1 % of the total load. Furthermore, a voltage-active power trajectory sensitivity index (VPTSI) at all load buses is calculated to provide information about the bus that has the most prevalent influence in enhancing the system stability. The bus with the highest VPTSI is then selected as the location of load shedding. This process is reiterated until the voltages at all buses are stable. \ud High penetration levels of DGs have made the problem of load shedding in this modern power system become more challenging. Therefore, more DGs in the power system will change the distribution system???s structure and will establish more nuisances to the load shedding. Hence, this thesis also assesses the load shedding design in power systems in regard to DGs. The proposed method of UVLS based on trajectory sensitivity is further improved to include the dynamic DG performance assessment. The DG evaluated in this study is a wind turbine driven doubly fed induction generator

Novel Hybrid Modified Modal Analysis and Continuation Power Flow Method for Unity Power Factor DER Placement

Distributed energy resource (DER) has become an effective attempt in promoting use of renewable energy resources for electricity generation. The core intention of this study is to expand an approach for optimally placing several DER units to attain the most stable performance of the system and the greatest power losses decrease. The recommended technique is established on two analytical methods for analyzing voltage stability: the new modified modal analysis (MMA) and the continuation power flow (CPF) or MMA–CPF methods. The MMA evaluates voltage stability by considering incremental connection relating voltage and active power, which includes the eigenvalue and the related eigenvectors computed from the reduced modified Jacobian matrix. Furthermore, an active participation factor (APF) is computed from the eigenvectors of the reduced modified Jacobian matrix. The CPF method uses a predictor–corrector stepping pattern to reach the solution track and compute the tangent vector sensitivity (TVS). Both APF and TVS indicate each load bus sensitivity in the network. In addition, an objective function regarding losses decrease and eigenvalue is expressed to calculate the best bus position for DER allocation. The proposed MMA–CPF technique has been assessed on a 34-bus RDN and the outcomes demonstrate the effectiveness of the proposed scheme

Novel Hybrid Modified Modal Analysis and Continuation Power Flow Method for Unity Power Factor DER Placement

Distributed energy resource (DER) has become an effective attempt in promoting use of renewable energy resources for electricity generation. The core intention of this study is to expand an approach for optimally placing several DER units to attain the most stable performance of the system and the greatest power losses decrease. The recommended technique is established on two analytical methods for analyzing voltage stability: the new modified modal analysis (MMA) and the continuation power flow (CPF) or MMA–CPF methods. The MMA evaluates voltage stability by considering incremental connection relating voltage and active power, which includes the eigenvalue and the related eigenvectors computed from the reduced modified Jacobian matrix. Furthermore, an active participation factor (APF) is computed from the eigenvectors of the reduced modified Jacobian matrix. The CPF method uses a predictor–corrector stepping pattern to reach the solution track and compute the tangent vector sensitivity (TVS). Both APF and TVS indicate each load bus sensitivity in the network. In addition, an objective function regarding losses decrease and eigenvalue is expressed to calculate the best bus position for DER allocation. The proposed MMA–CPF technique has been assessed on a 34-bus RDN and the outcomes demonstrate the effectiveness of the proposed scheme

Under voltage load shedding incorporating bus participation factor

Under voltage load shedding (UVLS) plays a vital part in power system control when the system is subjected to large disturbances. Load shedding has been employed for long time as the last remedy to preclude major power system failure which is activated by under frequency or under voltage relays. This paper proposes an advanced method for under voltage load shedding incorporating the bus participation factor method to determine the location of load shedding. The main motivation of this study is to attain a better performance of UVLS. The proposed methodology is implemented on a 3-machine 9-bus test system. Dynamic simulation is performed to validate the robustness of the proposed method