Power Distribution System Master Plan Study for Ghana Final Report
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No. Republic of Ghana Ministry of Energy Electricity Company of Ghana Northern Electricity Department of Volta River Authority Power Distribution System Master Plan Study for Ghana Final Report Supplemental Volume 3 Master Plan & Implementation Plan September 2008 JAPAN INTERNATIONAL COOPERATION AGENCY Chubu Electric Power Co., Inc. IL JR 08-033 [Table of Contents] Chapter 1 Master Plan for distribution network renewal, reinforcement, and extension................................................................................................................................. 1 1.1 Results of preparation of plans for primary substations and subtransmission lines.................1 1.1.1 Plans for ECG primary substations and subtransmission lines........................................... 1 1.1.2 Plans for VRA-NED primary substations and subtransmission lines............................... 10 1.2 Preparation of plans for distribution network renewal, reinforcement, and extension .........13 1.2.1 Distribution network renewal plan........................................................................................ 13 1.2.3 Distribution network extension planning .............................................................................. 18 1.2.3 Distribution network extension planning .............................................................................. 18 Chapter 2 Implementation Plan of the Master Plan......................................................... 19 Chapter 3 Economic and Financial Analysis of the Master Plan ............................. 26 3.1 Overview of the Master Plan ......................................................................................................26 3.2 Financial Analysis........................................................................................................................27 3.3 Economic Analysis .......................................................................................................................31 Chapter 1 Master Plan for distribution network renewal, reinforcement, and extension 1.1 Results of preparation of plans for primary substations and subtransmission lines 1.1.1 Plans for ECG primary substations and subtransmission lines (1) Plans for existing primary substations and subtransmission lines Attachment 1 presents the plans for existing ECG primary substations and subtransmission lines. The ECG has plans for 28 substation projects at a total cost of about USD58 million and 39 subtransmission line projects at one of about USD32 million by 2012. Funding sources (e.g., the GEDAP and Ghanaian government) have already been determined for most of these projects, but this is not the case for some. (2) Results for the major cities (Accra, Tema, Kumasi, and Takoradi) Sections (a) through (d) present the results for the four major urban areas in the ECG supply area, i.e., Accra, Tema, Kumasi, and Takoradi, respectively. (a) Planning results for the Accra system Figure 1 shows a diagram for the current 33-kV system in the Accra area. In 2008, the maximum demand was 458 MVA. The Accra system has two BSPs (Achimota and Mallam). About 65 percent of the power demand at peak times is supplied from the Achimota BSP. There is a large power flow in supply from the Achimota BSP to central Accra (on the Achimota-Airport section and between the K and D points, for example; the combined power flow value is 219 MVA). A total of 10 circuits of subtransmission lines (with a combined thermal capacity of 310 MVA) are used in these sections. N BSP T Primary Substation Sub-transmission line J Achimota M BSP Y 298MVA(65%) 9MVA C 58MVA 22MVA Q Airport 59MVA S 50MVA L 22MVA 169MVA P A D F 51MVA R K Mallam 79MVA X BSP V 2008 Maximum demand E 160MVA(35%) B G 458MVA Figure 1 Diagram of the current Accra 33-kV system 1 Figure 2 presents a diagram of the system as of 2012 upon implementation of the Ghana Energy Development and Access Project (GEDAP) and other existing projects in their entirety. In that year, the maximum peak demand would reach 516 MVA. Attachment 1 lists the existing projects in the Accra area. By 2012, GEDAP, the national government project, and other projects are anticipated to add a total of 480 MVA in transformer capacity and 334 km of subtransmission lines (through extensions). Furthermore, under the national government project, a third BSP is to be constructed in the eastern part of the Accra area. Analysis of the system as of 2012 found that there would not be any overload or voltage problems for the primary substations and subtransmission lines in the Accra area. The existing future plans for primary substations and sub-transmission lines are enough for the maximum demand in 2012. N T Existing Projects Nmai Djorn Kwabenya J M Achimota BSP Y 3rd BSP C 277MVA(50%) 79MVA(14%) Sowutom Q S Airport Darkuman L A P D F Trade Fair R K Mallam Cantonment X V BSP E 2012 Maximum demand 196MVA(36%) G Adabraka B 516MVA Dansoman Figure 2 Diagram of the Accra 33-kV system in 2012 Although there are no additional plans for the years following 2012, an analysis was made of the system over the years 2013 - 2017 to check for bottlenecks. This analysis found overload on the subtransmission line between the H (Achimota) and E points in the system diagram for 2016 shown in Figure 3. As shown in Table 1, the installation of an additional subtransmission line at the overload point was selected as the solution for the aforementioned bottleneck. Besides resolving the bottleneck in 2016, this step would prevent the occurrence of a bottleneck in 2017 (when the maximum peak demand would reach 609 MVA). 2 BSP N Primary Substation T Sub-transmission line Nmai Djorn Kwabenya H-E:240CUPILC, J 45.3MVA/2cct Achimota M 100% BSP 3rd BSP Y Loading C 335MVA(53%) 83MVA(13%) Sowutom Q S Airport Darkuman L A P D F Trade Fair R K Mallam Cantonment X BSP V E 2016 Maximum demand 216MVA(34%) G Adabraka B 590MVA Dansoman Figure 3 Diagram of the Accra 33-kV system in 2016 Table 1 Proposed project for the Accra system Year of Cost Facility name Bottleneck Countermeasure impleme (USD1,000) ntation - Installation of two new 630 - Subtransmission H(Achimota)-E ALXLPE circuits between H and 1,323 2016 line overload E (2 circuits x 6.3 km) (b) Planning results for the Tema system Figure 4 shows a diagram for the current 33-kV system in the Tema area. In 2008, the maximum peak demand was 160 MVA. The Tema 33-kV system is supplied from the Tema BSP. Figure 5 presents a diagram of the system as of 2012 upon implementation of the GEDAP and other existing projects in their entirety. In that year, the maximum peak demand would reach 190 MVA. Attachment 1 lists the existing projects in the Tema area. By 2012, GEDAP, the national government project, and other projects are anticipated to add a total of 200 MVA in transformer capacity and 140 km of subtransmission lines (through extensions). The system will be connected to the BSP built in the Accra area. Analysis of the system as of 2012 found that there would not be any overload or voltage problems for the primary substations and subtransmission lines in the Tema area. The existing future plans for primary substations and sub-transmission lines are enough for the maximum demand in 2012. 3 BSP Ashaiman Primary Substation Sub-transmission line Steelworks 55MVA Tema BSP 26MVA 160MVA B TTL Wahome 43MVA 41MVA Ferro Fabric To Accra Lashibi E A D 2008 Maximum demand GPHA 160MVA Figure 4 Diagram of the current Tema 33-kV system Dawhenya Existing Projects Community 25 Santeo Ashaiman Adjei Kojo Kpone Steelworks Tema BSP 190MVA B TTL Wahome To Accra Ferro Fabric Lashibi E A D 2012 Maximum demand 190MVA GPHA Figure 5 Diagram of the Tema 33-kV system in 2012 Although there are no additional plans for the years following 2012 in the Tema area either, an analysis was made of the system over the years 2013 - 2017 to check for bottlenecks. This analysis found overload on the subtransmission line between the H (Tema) and E points in the system diagram for 2016 shown in Figure 6. As shown in Table 2, the installation of an additional subtransmission line at the overload point was selected as the solution for the aforementioned bottleneck. Besides resolving the bottleneck in 2016, this step would prevent the occurrence of a bottleneck in 2017 (when the maximum peak demand would reach 4 240 MVA). BSP Primary Substation Dawhenya Sub-transmission line Community 25 Santeo Ashaiman Adjei Kojo Kpone Steelworks Tema BSP 240MVA B TTL Wahome Ferro Fabric Lashibi E 102% Loading A D 2016 Maximum demand H-A:500CUXLPE, 229MVA GPHA 48.4MVA/1cct Figure 6 Diagram of the Tema 33-kV system in 2016 Table 2 Proposed project for the Tema system Year of Cost Facility name Bottleneck Countermeasure impleme (USD1,000) ntation - Installation of two new 630 - Subtransmission H(Tema)-A ALXLPE circuits between H and 588 2016 line overload E (1 circuits x 5.6 km) (c) Planning results for the Kumasi system Figure 7 shows a diagram for the current 33-kV system in the Kumasi area. In 2008, the maximum peak demand was 174 MVA. The Kumasi 33-kV system is supplied from the Kumasi BSP. Figure 8 presents a diagram of the system as of 2012 upon implementation of the GEDAP in its entirety. In that year, the maximum peak demand would reach 211 MVA. Attachment 1 lists the existing projects in the Kumasi area. By 2012, the GEDAP is anticipated to add a total of 120 MVA in transformer capacity and 52 km of subtransmission lines (through extensions). A second BSP is to be constructed in the eastern part of the Kumasi