Mahmut Erkut Cebeci

Transmission and substation expansion planning using Mixed Integer Programming

This paper presents a novel planning approach which optimizes size and location of new transmission substation (TS) investments considering capacity expansion of the existing TSs based on primary distribution network investment requirements. Mixed Integer Programming (MIP) is utilized and the problem is decomposed into investment and feasibility check subproblems. The algorithm is formulated to minimize total investment cost while supplying the spatial forecasted load considering a set of system constraints. The results of two numerical examples indicate that presented algorithm is adequate for determining requirements of new transmission substations and/or capacity expansions together with new HV/MV lines, via appropriate selection of candidates. Visualization of the planning algorithm results, in an iterative manner, gives very important verification signals regarding the necessity of the proposed investments.

A geographical zoning methodology for nodal transmission use-of-system tariffs

Power systems are generally separated into transmission use-of-tariff (TUoT) zones to simplify the tariff mechanism, particularly for large grids. Each zone is an aggregation of neighboring nodes with similar tariffs that are determined based on long-run marginal cost (LRMC) calculations. This paper proposes a zoning methodology which ensures diversification of zonal tariffs while geographically aggregating the nodal TUoTs by weighted average approach. Investment cost-related pricing (ICRP) and DC-load-flow pricing (DCLFP) methods are utilized in computing the LRMC based nodal tariffs. Performance of the LMRC based pricing methods, sensitivity of the economical parameters on the results, and the proposed zoning approach are investigated for a simple 12-bus generic power system. Given the satisfactory results, TUoT zones of Turkish power network are determined with the proposed zoning algorithm for the tariff period of 2012-2014.

Lessons learnt from interfacing ArcGIS and DIgSILENT powerfactory at Başkent DISCO

Smart grids require not only smart tools to automatize grid operation and planning processes but also require smart approaches to maximize utilization of the capabilities of those tools as well. Geographic information systems (GIS) provide an integrated suite of software for visualizing the system data, tools for network optimisation, and a range of automation and information processing systems which assist in the operation, maintenance and planning of distribution networks. Interfacing of GIS data with sophisticated power system simulation tools facilitates model updating process for the network planner who needs updated network data for operational and planning analysis. Quality and quantity of data in GIS database generally limit the planners. This paper presents a smart process for interfacing GIS based database with power system simulation tools, based on the lessons learnt from interfacing ArcGIS with DIgSILENT PowerFactory at Başkent DISCO.

Alçak Gerilim Ekspres Fider Uygulaması ile Sezonsal Yüklenme Farkları Yüksek Olan Dağıtım Transformatörlerin Boşta Kayıplarının Azaltılması

Bu calismada, Akdeniz’de kiyisi olan isletmelerde yazliklarin yogun oldugu bolgelerde, yaz sezonu puant yuklenme seviyelerine gore kapasiteleri secilen dagitim transformatorlerin, sezon harici donemlerdeki teknik kayiplarinin minimize edilmesine yonelik tasarlanan alcak gerilim ekspres fider (AGEF) uygulamasinin teknik-ekonomik fizibilite analizleri ve sahada pilot uygulamasi aciklanmistir. AGEF uygulamasi, birbirine yakin iki dagitim transformatorunun AG ana baralarinin kablo ile birbirine baglamasi suretiyle, transformatorlerden biri devre disi iken diger transformator uzerinden her iki transformatorun de yuklerinin beslenmesi prensibine dayanir. Uygulamada onemli olan husus, guvenlik nedeniyle transformatorlerin AGEF uzerinden paralel calismasinin onlenmesidir. Calismada bu amacla bir kilitleme mekanizmasi da tasarlanmistir. Teknik analizler kapsamindaki gerilim dusumu ve teknik kayip analizleri DIgSILENT PowerFactory™ sebeke analiz yazilimi ile gerceklestirilmistir. AGEF uygulamasinda one cikan transformatorler onceliklendirme gostergeleri ile belirlenmistir. Elde edilen bulgular isiginda, Akdeniz Bolgesinde elektrik dagitim faaliyeti gosteren Toroslar Elektrik Dagitim A.Ş.’nin (EDAŞ) sorumluluk bolgesinde bulunan Karatas Ilcesinde, yazliklarin yogun oldugu ve dolayisiyla sezonsal yukun buyuk olcude degisiklik gosterdigi bir bolgede pilot uygulama gerceklestirilmistir.

Protection relay settings management at Akdeniz DISCO through DIgSILENT StationWare

Number of setting values of relays has increased considerably with the replacement of electro-mechanical relays to digital relays recently. Moreover, increase in the number of distributed and renewable generators connected to distribution grids complicates the protection relay coordination process. Essentially, settings of protection devices should be managed more carefully than before in a systematical way. This paper presents the protection relay settings management at Akdeniz DISCO through DIgSILENT StationWare software platform. The platform is utilized to manage relay setting process beginning from the relay coordination analysis phase to final implementation phase on site. The software is configured to allow remote access to relay setting management platform by different level of users which have different level of permissions depending on their roles in the whole process.

Feasibility of distributing electric power through single-phase transformers at rural regions of Turkey based on rural characteristic indices

Single-phase (1-phase) transformers have been utilized in some countries to supply rural distribution regions which particularly have relatively low load densities (farms, villages, etc.). Leading countries include US, Canada, Mexico, New Zealand, and Australia. However, utilization of 1-phase transformers is very limited (almost negligible) at European countries. Turkey is among those countries in which electric is supplied through three-phase transformers regardless of the load density of the region to be supplied. The main objective of this paper is to quantify the technical and financial benefits of installing 1-phase transformers instead of three-phase transformers at the distribution network of Yeşilırmak Distribution Company (YEDAS) which shows very high rural characteristic in Turkey. Single- and three-phase transformer alternatives are compared technically based on computer simulations including voltage drop, technical losses and reliability. Pilot regions are defined considering their prevailing rural characteristics based on some metrics defined in this paper. The results show that distribution of power through 1-phase transformers by either single-wire-earth-return (SWER) or double-phase techniques are promising for YEDAS particularly for the rural regions which have highly rural characteristics.

Informatics Solutions for Smart Trading on Wholesale Electricity Markets Containing RES Bidders

This paper presents an informatics solution that aims to assist energy suppliers in setting up their bids on wholesale electricity markets. The solution is developed into a cloud computing platform as an online dashboard, including the following components: consumption optimization and forecasting, generation forecasting, advanced data analytics, and decision rules. These components require a complex data integration model that gathers data from different sources such as: smart meters and appliances, SCADA systems and wholesale electricity market.

Implementation of 1 kV on LV feeders: A smart alternative to MV line investments to solve voltage drop problems at LV systems

This paper presents methodology and on-site pilot implementation of utilizing 1 kV at low voltage (LV) feeders as an alternative to medium voltage (MV) line investments to solve voltage drop problems at LV systems. Typically distribution companies solve voltage drop problems of LV system by installing a new MV/LV transformer and transferring outmost loads of the existing transformer to the new transformer. This necessitates installation of MV line between the existing and new transformer. The implementation of 1 kV on the existing LV lines eliminates the need for MV line investment. It can be an alternative solution at those regions where MV line investment is challenging due to land use issues or bureaucratic concerns. In addition, the study shows that 1 kV implementation could be cost effective than the traditional MV expansion. Furthermore, such an implementation provides more flexibility to the operators, as addressed in the study.

Optimization of long-term investments of electric distribution systems considering planning metrics

This paper presents a dynamic planning algorithm methodology which optimizes long-term primary electric distribution network investments considering planning metrics. An algorithm which calculates a representative primary network model of distribution grids, whose primary and secondary networks are intricate, is developed. It is aimed to facilitate assessment of primary distribution network investment requirements and thereby defining grid investment candidates effectively. A planning algorithm, which considers representative primary network model and candidate planning investments as inputs, is developed based on a mixed integer programming (MIP) technique. Some planning metrics are defined in order to technically and economically assess optimum investments along the planning horizon. DIgSILENT PowerFactory (PF) software is utilized in technical analysis to assess impacts of candidate grid investments on technical constraints. The algorithms and planning metrics developed in the study are tested satisfactorily on pilot regions of Akdeniz Electric Distribution Company in Turkey.

Theoretical and practical aspects of implementing a low voltage express feeder between nearby distribution transformers to reduce annual losses

Capacity of distribution transformers is usually determined based on peak demand forecasted along a planning period. Peak demand actualizes at different seasons depending on the load characteristics of the transformers. For example, transformers at coastal towns essentially experience peak demand during summer periods. Although such transformers are loaded up to their capacities at summer seasons, their loading level reduces drastically during the off-season periods. This study addresses technical losses of such transformers and presents a solution to reduce the total transformer losses by means of implementing a low voltage express feeder (LVEF) between transformers close by. Total load of two nearby transformers is supplied by only one of the transformers through the LVEF while the other transformer is de-energized during off-season period. Depending on the criteria addressed in this study, this approach enables a decrease in the annual total loss of the system. Study includes a pilot implementation on-site.