Radial System Reconfiguration to Minimize Operating Costs in Markets

Author(s):  
S. Chandramohan ◽  
R. P. Kumudini Devi ◽  
Bala Venkatesh

The operating cost of a radial distribution system may be minimized by reducing the amount of real power and reactive power drawn from the transmission system. Presently, real power is being priced through a market clearing scheme all over North America. Reactive power is an ancillary service and its supply would be priced appropriately in the near future through a clearing market structure. A recent US Federal Energy Regulatory Commission staff report [1] has initiated a discussion on the formulation of a reactive power market. When such a market is designed and operated, large customers (distribution corporations) will have to purchase reactive power along with real power from the transmission corporation through an independent system operator. Envisaging such a prospect, this paper proposes a new method of reconfiguring radial systems considering costs of real and reactive power while maintaining an appropriate voltage profile and level of reliable power supply. The proposed method is tested on sample test systems and reported.

Distributed generation system penetration in the existing distribution system is done for minimizing the losses and improving the voltage profile. There are total five types of distributed generation systems exist based on their power delivery like distributed generation system injecting real and reactive power, supplying real power only, supplying reactive power only, absorbing reactive power only , supplying real power and absorbing reactive power. All these five types of distributed generation systems have different penetration effects on the radial distribution system. We get different voltage profiles and power losses for different types of distributed generation systems. The testing of these five types of distributed generation systems will be done on IEEE 33 bus radial distribution system. For computing, the line parameters and power losses of the above testing system the forward-backward sweep load flow method will be applied


2012 ◽  
Vol 1 (2) ◽  
pp. 56 ◽  
Author(s):  
M. Rostamzadeh ◽  
K. Valipour ◽  
S. J. Shenava ◽  
M. Khalilpour ◽  
N. Razmjooy

This paper proposes an Imperialist Competitive Algorithm (ICA) for optimal multiple distributed generations (DGs) placement and sizing in a distribution system. The objective is to minimize the total real power losses and improve the voltage profile within real and reactive power generation and voltage limits. Three types of DG are considered and the ICA is used to find the better sizes and locations of DGs for maximum real power losses reduction and voltage improvement for given number of DG units in each type. Both integer and continuous variables are considered in ICA, integer variable for locations and continues variable for sizes. The total real power losses and voltage profile evaluation are based on a power flow method for radial distribution system with the representation of DGs. The proposed method has been demonstrated on 33 bus radial distribution system. The efficiency of the ICA in reducing the total power losses and improving voltage is validated by comparing the obtained results with Particle Swarm Optimization (PSO) algorithm.


Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3442
Author(s):  
Fábio Retorta ◽  
João Aguiar ◽  
Igor Rezende ◽  
José Villar ◽  
Bernardo Silva

This paper proposes a near to real-time local market to provide reactive power to the transmission system operator (TSO), using the resources connected to a distribution grid managed by a distribution system operator (DSO). The TSO publishes a requested reactive power profile at the TSO-DSO interface for each time-interval of the next delivery period, so that market agents (managing resources of the distribution grid) can prepare and send their bids accordingly. DSO resources are the first to be mobilized, and the remaining residual reactive power is supplied by the reactive power flexibility offered in the local reactive market. Complex bids (with non-curtailability conditions) are supported to provide flexible ways of bidding fewer flexible assets (such as capacitor banks). An alternating current (AC) optimal power flow (OPF) is used to clear the bids by maximizing the social welfare to supply the TSO required reactive power profile, subject to the DSO grid constraints. A rolling window mechanism allows a continuous dispatching of reactive power, and the possibility of adapting assigned schedules to real time constraints. A simplified TSO-DSO cost assignment of the flexible reactive power used is proposed to share for settlement purposes.


SCITECH Nepal ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. 1-7
Author(s):  
Avinash Khatri KC ◽  
Tika Ram Regmi

An electric distribution system plays an important role in achieving satisfactory power supply. The quality of power is measured by voltage stability and profile of voltage. The voltage profile is affected by the losses in distribution system. As the load is mostly inductive on the distribution system and requires large reactive power, most of the power quality problems can be resolved with requisite control of reactive power. Capacitors are often installed in distribution system for reactive power compensation. This paper presents two stage procedures to identify the location and size of capacitor bank. In the first stage, the load flow is carried out to find the losses of the system using sweep algorithm. In the next stage, different size of capacitors are initialized and placed in each possible candidate bus and again load flow for the system is carried out. The objective function of the cost incorporating capacitor cost and loss cost is formulated constrained with voltage limits. The capacitor with the minimum cost is selected as the optimized solution. The proposed procedure is applied to different standard test systems as 12-bus radial distribution systems. In addition, the proposed procedure is applied on a real distribution system, a section of Sallaghari Feeder of Thimi substation. The voltage drops and power loss before and after installing the capacitor were compared for the system under test in this work. The result showed better voltage profiles and power losses of the distribution system can be improved by using the proposed method and it can be a benefit to the distribution networks.


Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 419
Author(s):  
Mads Nannestad ◽  
Zhe Zhang ◽  
Jundi Jia ◽  
Emil Jensen ◽  
Peter Randewijk

This paper investigates the reactive power balance of the Zealand side of the Danish transmission system (DK2) by using QV-curves. The study is performed in cooperation with Energinet, who is the Danish transmission system operator (TSO). Firstly, this paper aims to map the reactive power balance with the current challenges in the system, which appears due to a decision of changing overhead lines in the scenic area to cables. Secondly, a method is derived for obtaining a comprehensive overview of the impacts that future projects might have on the system. By dividing the transmission system into smaller areas, it is possible to analyze how the reactive power will affect the voltage; moreover, it is favorable to analyze and handle the challenges in the reactive power balance locally. This helps the TSO to quickly determine the lack of reactive power devices and issues that might occur in future expansions of the system. For this paper, a full-scale model of DK2 and SCADA-data has been utilized. It covers the period from 01-01-2016 to 20-08-2017 between the TSO and the Distribution System Operator (DSO). The studies have shown how the location of the wind production will create issues in the reactive power balance.


Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4028 ◽  
Author(s):  
Abreu ◽  
Soares ◽  
Carvalho ◽  
Morais ◽  
Simão ◽  
...  

Challenges in the coordination between the transmission system operator (TSO) and the distribution system operator (DSO) have risen continuously with the integration of distributed energy resources (DER). These technologies have the possibility to provide reactive power support for system operators. Considering the Portuguese reactive power policy as an example of the regulatory framework, this paper proposes a methodology for proactive reactive power management of the DSO using the renewable energy sources (RES) considering forecast uncertainty available in the distribution system. The proposed method applies a stochastic sequential alternative current (AC)-optimal power flow (SOPF) that returns trustworthy solutions for the DSO and optimizes the use of reactive power between the DSO and DER. The method is validated using a 37-bus distribution network considering real data. Results proved that the method improves the reactive power management by taking advantage of the full capabilities of the DER and by reducing the injection of reactive power by the TSO in the distribution network and, therefore, reducing losses.


2017 ◽  
Vol 26 (4) ◽  
pp. 81
Author(s):  
Manju Aggarwal ◽  
Madhusudan Singh ◽  
S.K. Gupta

In a low voltage distribution system with integrated wind plant, voltage stability is impacted by the large variation of load and wind penetration. The compensators like SVC and DSTATCOM are currently being used to address such issue of voltage instability. This paper analyses the impact of wind penetration and variation of active and reactive power of the load on voltage profile of a wind generation system with and without DSTATCOM. It also analyses the performance of the system during fault by calculating various parameters of the system. It has been demonstrated that voltage stability margin increases using DSTATCOM at different wind penetration levels. This system has been simulated and analysed in MATLAB 2011b using a power system toolbox under steady state and transient conditions.


2020 ◽  
Vol 01 (04) ◽  
pp. 150-169
Author(s):  
Sk. Md. Golam Mostafa ◽  
Jai Govind Shingh ◽  
H.M. Enamul Haque

The main goal of power utilities is to supply reliable and quality power to the end-users and fulfill their total demands at all possible locations. Most of the loads are connected in the distribution systems are inductive. The excessive reactive power demand over the distribution network causes tremendous reactive power losses and changes the voltage profile, hence the system's reliability. Shunt Capacitor Bank (SCB) is widely used in the distribution system for reactive power support, voltage profile, and system performance improvement. But there are some challenges to employ SCB in the distribution network; among them, ensuring the most optimum location and size is a big challenge to get the maximum benefits. Some existing techniques showed better loss reduction but needed either larger SCBs sizes or cause improper node voltage. In this research study, the first section provides an extensive literature review of optimal SCBs placement and sizing. Later on, a new technique called Combinatorial Method has been developed for sizing and sitting of optimal Shunt Capacitors to reduce the distribution loss significantly. The developed method was tested for different case studies using Indian practical 22-bus and IEEE-69-bus network. The results were compared with DSA, Fuzzy GA, and TLBO method and found better distribution feeder loss minimization and voltage profile improvement.


Author(s):  
Su Hlaing Win ◽  
Pyone Lai Swe

A Radial Distribution network is important in power system area because of its simple design and reduced cost. Reduction of system losses and improvement of voltage profile is one of the key aspects in power system operation. Distributed generators are beneficial in reducing losses effectively in distribution systems as compared to other methods of loss reduction. Sizing and location of DG sources places an important role in reducing losses in distribution network. Four types of DG are considered in this paper with one DG installed for minimize the total real and reactive power losses. The objective of this methodology is to calculate size and to identify the corresponding optimum location for DG placement for minimizing the total real and reactive power losses and to improve voltage profile   in primary distribution system. It can obtain maximum loss reduction for each of four types of optimally placed DGs. Optimal sizing of Distributed Generation can be calculated using exact loss formula and an efficient approach is used to determine the optimum location for Distributed Generation Placement.  To demonstrate the performance of the proposed approach 36-bus radial distribution system in Belin Substation in Myanmar was tested and validated with different sizes and the result was discussed.


At present the green environment plays a crucial part in fighting against the global warming. The Electric Vehicles which are eco-friendly provides the solution for these environmental issues which promotes low carbon emission. In the present scenario variation of the power flow and voltage profile at specific nodal junctions in a radial distribution system, when Electric Vehicle has been connected as a load is essential This paper shows the potential drop analysis on a distribution system with Electric Vehicle as a load. The results provide the total real power loss, total reactive power loss occurs in the radial test bus system and the voltage magnitude at nodes for an IEEE standard bus system. The Backward/Forward sweep method has been implemented on IEEE test bus radial distribution system. Various types of loads such as residential, commercial, and industrial with Electric Vehicles are considered for testing. The results indicate that a drop in voltage when Electric Vehicles has been integrated into the grid along with other consumers. The programming results has been compared with standard values and found to be satisfactory. Suggestions’ for improving the voltage profile had also included in this paper.


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