SUMMARY - RELATIONSHIP BETWEEN QUALITY OF SERVICE DEMANDED AND TARIFF

Transcription

1 SUMMARY - RELATIONSHIP BETWEEN QUALITY OF SERVICE DEMANDED AND TARIFF PA Consulting Services SA Authors: C. Guidi / J. Espain - / J. García Argentina Restructuring of Electric Sectors in Latin America has been characterized by the concession of service supply, establishing: a) the quality conditions under which such service should be provided; b) a penalty regime in the case of verifying non compliance with such conditions; and c) maximum tariffs to be charges for the service. Thus, in each case, an implicit relationship between the price paid by the customer and the service and the related quality was established. Even though these aspects were evaluated by the different bidders when they submitted their offers for the different areas given in concession, they had no definite experience about the implications of this type of regime, and after a certain period of application, similar concerns started to arise in various countries whether it was possible to provide the service according to the quality demands established and if tariffs really reflected the service supply under those conditions. This situation reached various degrees of relevance depending on the characteristics of the concessions and quality regimes in each country, but in general terms it gave way to the beginning of some research about this particular subject. The natural opportunity has been the moment of the tariff review, which generally takes place every 4 years, counted from the take-over date. predictable quality, have proved to be within the limits established. In some cases, there is evidence of limits way below the admissible ones. Values also presented a significant similitude among themselves and a good relationship with their Distribution Costs. As regards areas, the opposite situation was verified. In most of the cases, the resulting simulation values proved the impossibility of complying with the demand levels established, as well as the presence of a great dispersion among the results obtained, depending mainly on the facilities characteristics, in particular, the feeders length. In these cases, the absence of a relationship between Distribution Costs incorporated in tariffs and the quality of service predicted to be obtained through an efficient network management was verified. In most of the cases it was also verified that the necessary costs to increase quality of service levels are of a magnitude comparable to the Distribution Cost itself, even not making it possible to achieve the demanded levels. Some countries have undertaken studies tending to determine if the typical circuits for each type of area to serve enabled to provide the service according to the requirements established in the quality standards, as well as the economic impact of the standard application regarding the necessary resources for the execution of the requested controls and their relationship with tariff. The results obtained prove that quality requirements might not be in agreement with tariffs in some of the served areas. In some cases, they are even impossible to comply with considering the network configuration considered in tariff determination. This situation has led to more in-depth studies about the actual companies networks in order to determine their relationship with the typical circuits considered for tariff determination and with the quality of service levels demanded. These studies have yielded different results depending on the characteristics of the area served. The conclusions are that in all the cases analyzed for areas, the simulations results as regards the

2 RELATIONSHIP BETWEEN QUALITY OF SERVICE DEMANDED AND TARIFF Authors: C. Guidi / J. Espain - / J. García PA Consulting Services SA Argentina SYNOPSIS: depending on the characteristics of the area served. These results will be presented in this paper. Restructuring of Electric Sectors in Latin America has been characterized by the concession of service supply, establishing: a) the quality conditions under which such service should be provided; b) a penalty regime in the case of verifying non compliance with such conditions; and c) maximum tariffs to be charges for the service. Thus, in each case, an implicit relationship between the price paid by the customer and the service and the related quality was established. Even though these aspects were evaluated by the different bidders when they submitted their offers for the different areas given in concession, they had no definite experience about the implications of this type of regime, and after a certain period of application, similar concerns started to arise in various countries whether it was possible to provide the service according to the quality demands established and if tariffs really reflected the service supply under those conditions. This situation reached various degrees of relevance depending on the characteristics of the concessions and quality regimes in each country, but in general terms it gave way to the beginning of some research about this particular subject. The natural opportunity has been the moment of the tariff review, which generally takes place every 4 years, counted from the take-over date. Some countries have undertaken studies tending to determine if the typical circuits for each type of area to serve enabled to provide the service according to the requirements established in the quality standards, as well as the economic impact of the standard application regarding the necessary resources for the execution of the requested controls and their relationship with tariff. The results obtained prove that quality requirements might not be in agreement with tariffs in some of the served areas. In some cases, they are even impossible to comply with considering the network configuration considered in tariff determination. This situation has led to more in-depth studies about the actual companies networks in order to determine their relationship with the typical circuits considered for tariff determination and with the quality of service levels demanded. These studies have yielded different results RELATIONSHIP BETWEEN QUALITY OF SERVICE DEMANDED AND TARIFF Methodology The quality of service supplied by a distribution company is generally evaluated through a series of performance indicators that monitor service technical and commercial aspects. The present paper focuses on the technical aspects (Technical Service and Product), since they are closely related to the network characteristics and the market they serve. As regards the Technical Product, only the voltage level has been analyzed and as to the Technical Service, outage frequency and duration indicators have been contemplated. In every case and through a simulation, the analysis has been based on the determination of the quality expected to be obtained in networks of various characteristics operated under efficiency conditions and quality has been associated with distribution costs that are representative of those characteristics. The results obtained have been considered through multiple studies made in various countries of Latin America, such as Peru, Chile and Argentina, as a result of a tariff revision or a particular research on the predictable quality conditions. For the purposes of the present analysis, three types of markets served by networks of various characteristics have been selected. High-Density, and. The markets analyzed have turned out to be comparable among themselves, and even though there are peculiarities in the facilities serving them, depending on the company and country analyzed, the main common characteristics in each one of them have been the following: High-density urban market is characterized for being supplied through underground networks and MV/LV transforming modules over 6 kva. Facilities associated to the urban-type market are characterized

3 by overhead pole networks and MV/LV transforming modules in the order of 3 kva. As regards the rural type market, the facilities characteristics serving it are long-length MV network and small capacity MV/LV transformers. The following figures schematize the representative circuits of each one of the cases under analysis. High-Density Market HV Overhead Pole Two HV transmission line MV HV Line Cliente Especi HV/ MV transf. LV Underground Diversion LV MV/ LV Transf. MV Closure MV Supply Technical Service Interruptions LV MV Supply Underground network Market 1x25 kva Cliente Especi HV/ MV Transf. k1 x 25 MVA MV One HV transmission line Cierre en extremos The analysis tasks performed comprised the simulation of the typical circuit behavior considered in the VAD calculation, in the countries where tariff calculations are based on this methodology and the behavior simulation of the actual networks, operated under efficiency conditions, for the areas that are representative of each one of the markets under study. Simulations comprised the HV and MV network up to the MV/LV terminals, since in average terms 9 % of the interruption impacts undergone by users are originated in these facilities. Through this methodology, maps of the predictable quality could be elaborated through an efficient management of the networks of each MV/LV transforming center, as indicated in the Figure below. LV network Aerial closure MV/ LV. Tranf. LV Network Market

4 The results of the simulations performed for the different cases analyzed, consolidated by type of market served, are summarized in the figures below. Interruptions Frequency/semester Duration Time/Semester (hs) High Density Max. Freq. Min.Freq. Avge Freq. High Density Max. Time Min. Time Avge. Time Results have proved a great value homogeneity for High-Density cases and a great value dispersion in the case of rural markets, depending mainly on the characteristics of their length. As regards the impact produced on the different voltage level facilities, a high HV network participation has been evident as regards area interruption level, decreasing towards the lower density areas, and showing an insignificant participation in areas. % interruption impact 1% 9% 8% 7% 6% 4% 3% 2% 1% % HV Network. MV Network As regards the participation of the main components of the facilities for each type of network analyzed, the impact of each component in the number and duration of the interruptions has proved to depend mainly on the topology and configuration of each type of network. The following figures show the impact percentage of each element in the Interruption Duration (D) and the Number of Interruptions (N). High-Density Area 9% 6% 46% FUS TRAFOS SECC LINES INTER R6KV 41% 18% 23% 9% % D PARTICIPATION % N PARTICIPATION Area 11% 36% 6% 29% FUS SECC TRAFOS LINES INTER R6KV 29% 3% 4% 5 % D PARTICIPATION % N PARTICIPATION As a result of the comparison of the values obtained with the demand levels established in each particular case, compliance with those values in general terms has been verified in high-density urban areas and urban areas. In the case of areas, non compliance has been verified practically in all demand cases. In the case of areas, various operation and control devices have been incorporated to the simulation in order to improve frequency and duration indicators, such as telecontrol, re-connectors and isolating switches, which were taken into account at the moment of determining the network payment value for the tariff calculation. Technical Product Voltage Level As to Voltage Level, since this parameter is habitually pre-established when the facilities are designed, the results of the simulations run on the typical circuits proved the compliance with design conditions. In the

5 case of actual networks operated in an efficient way, the values obtained have resulted in voltage drop between 5 % and 7 % for MV network, and between 8 % and 1 % in LV network in areas, and between 8 % and 11 % in the MV network in areas. In the case of areas, it has been necessary to incorporate a simulation of the voltage regulator operation throughout the facilities, resulting in some cases a significant number, that was considered for payment remuneration of the networks at the moment of the tariff calculation. great homogeneity and almost linear relationship among them has turned out for the High-Density area, turning this area into one where both values are perfectly predictable. This situation brings about dispersion areas, depending on the particular features of the networks within which both quality levels and distribution costs are predicted to be. The following graphs represent interruption frequency and time values predictable for each one of the areas under study based on their corresponding distribution costs. 12 Distribution-Related Costs Distribution cost values associated to each one of the facilities that are representative of the areas analyzed present some variations brought about by the various methodologies used for the calculations and to differences in costs, calculation dates and type of related equipment, typical of each company and country studied. Furthermore, the analysis made has performed an adequate value comparison and association, resulting in a value alignment in cases and a huge dispersion in the cases, which might be considered as a reference in the subject. The Figure below represents all quality indicators together, representative of frequency and duration of the interruptions and distribution costs associated to each one of the areas analyzed. Frquency/Semester Max. Freq. Min. Freq. Avge. Freq. Max. Time Min. Timen Avge. Time US$/kW-mes Hours/ Semester US$/kW-month It may be observed that even though there is a similar tendency in cost curves with those of the quality of service predictable for each type of networks, the latter show a greater dispersion. Dispersion in quality levels associated to rural areas is due to the fact that the analysis included facilities with very different extensions, in some cases even up to 5 times longer than the lengths between them. The great dispersion in quality levels is not related to the unit capacity costs. As a result of the analysis and by connecting the quality of service values predictable for the various types of networks with the corresponding distribution costs, a Frequency/Semester Hours/Semester US$/kW-month US$/kW-mes The verified linearity for the High Density area may be observed, as well as the increasing value dispersion towards the area. Conclusions To conclude, it may be mentioned that in all the cases analyzed for areas, the simulations results as regards the predictable quality, have proved to be within the limits established. In some cases, there is evidence of limits way below the admissible ones. Values also presented a significant similitude among themselves and a good relationship with their Distribution Costs. As regards areas, the opposite situation was verified. In most of the cases, the resulting simulation values proved the impossibility of complying with the demand levels established, as well as the presence of a great dispersion among the results obtained, depending mainly on the facilities characteristics, in particular, the feeders length. In these cases, the absence of a relationship between Distribution Costs incorporated in tariffs and the quality of service predicted to be obtained through an efficient network management was verified. In most of the cases it was also verified that the necessary costs to

6 increase quality of service levels are of a magnitude comparable to the Distribution Cost itself, even not making it possible to achieve the demanded levels.