Vol. 1 No. 3 Aug. 2018 Global Energy Interconnection DOI: 10.14171/j.2096-5117.gei.2018.03.007 www.geidco.org

Full-length article

Identification of system vulnerabilities in the Ethiopian electric power system

Moges Alemu Tikuneh1, Getachew Biru Worku2 1. Department of Electrical and Computer Engineering, Debre Berhan University, Debre Berhan, Ethiopia 2. School of Electrical and Computer Engineering, Addis Ababa University, AAiT, Addis Ababa, Ethiopia

Abstract: The Ethiopian Electric Power (EEP) has been operating and managing the national interconnected power system with dispersed and geographically isolated generators, a complex transmission system and loads. In recent years, with an increasing load demand due to rural electrification and industrialization, the Ethiopian power system has faced more frequent, widely spread and long lasting blackouts. To slash the occurrence of such incidents, identifying the system vulnerabilities is the first step in this direction. In this paper, the vulnerability assessment is performed using indices called active power performance index (PIp) and voltage performance index (PIv). These indices provide a direct means of comparing the relative severity of the different line outages on the system loads and voltage profiles. Accordingly, it is found that the most severe line outages are those lines that interconnect the high load centered (Addis Ababa and Central regions) with the rest of the regional power systems. In addition, the most vulnerable buses of the network in respect of voltage limit violations are mainly found at the high load centers.

Keywords: Power grids, power systems, vulnerability assessment, transmission system.

1 Introduction the power system, and thereby the national grid system’s vulnerability is increased from time to time. The past decade has witnessed a big growth in The main HV levels of the power transmission Ethiopia’s electricity sector. Between 2012 and 2016, systems are 400 kV, 230 kV, and 132 kV. The 500 kV the number of electricity customers of EEP reached over transmission system is on the way to come. Among four million from two million at the beginning of the the voltage levels, the 400 kV and 230 kV are the most period [1]. This steep growth in the electricity sector has important and are responsible for the bulk power flows led to significant constraints in EEP. Moreover, while the among the eight regional power systems: viz. Addis generation has been at the forefront of energy developments Ababa, Central, Western, Southwestern, Northwestern, in Ethiopia, the weaknesses in the transmission network Eastern, Northern and Northeastern regions. In addition, are not receiving their due attention. These weaknesses the power transmission network is extended to Djibouti affect the customers, the government, the economy and in the east and to the Republic of Sudan to the northwest. social welfare of the society. Due to these facts, fault(s) in The HV transmission network consists of 1071.76 km of the transmission system are threatening the operation of 400 kV circuits, 5895.54 km of 230 kV circuits and 4666.79 km of 132 kV circuits [1]. In Ethiopia, the power system’s vulnerability has

Received: 20 November 2017/ Accepted: 12 December 2017/ Published: worsened from time to time because of the implicit and 25 August 2018 explicit reasons. However, these reasons have not been Moges Alemu Tikuneh studied in a concrete way which further exacerbate [email protected] the situation and as a result partial and total blackouts Getachew Biru Worku (PhD), frequently happen on the grid. Therefore, this paper [email protected] presents an approach for assessing vulnerability of the EEP

358 Moges Alemu Tikuneh et al. Identification of system vulnerabilities in the Ethiopian electric power system system by using two indices, called performance indices where

(PIs) which reflect the health of the system. The indices Vi – The voltage magnitude corresponding to bus i SP allow assessing two different symptoms of system stress Vi – Specified voltage magnitude corresponding to such as voltage limit violations and overloads. bus i This process of vulnerability analysis involves studying n – A positive number and usually its value is 1 (n = 1, 2, … the effect of the removal of a system component on the etc...). system, particularly the power flows and the bus voltages. NB – Number of buses in the system whose voltage This component can be a generator, transmission line, magnitude is out of the specified ranges. transformer, and so on. This work however focuses on w – Real non-negative weighting factor (in general w = outages of the transmission network. The reason is that 1). most of the previous partial and total blackouts happened Thus, this index measures the severity of the out of limit as results of the faults on the transmission lines, as reported bus voltages and provides a direct means of comparing the by National Load Dispatch Center of EEP (NLDC) in [2]. relative severity of the different line outages on the system What follows is a qualitative and quantitative evaluation of voltage profile. which line outages lead to the most issues with regard to 2.2 Line Outage’s Severity Ranking voltage limit and line load violations. The method used to rank vulnerabilities is taken from Ranking is performed for all branch outages against [3], [4], [5], and [6]. Detailed explanation is given in their rated power carrying capacity (i.e., a load of 100%), Section II. and considering voltage violations outside the range of 0.9 pu to 1.1 pu. The most severe line outages and the 2 Vulnerability Assessment Methods performance indices for the two criteria are shown in descending order in Fig. 1 and 2. 2.1 Performance Indices The system performance index is a measure that can Line loading performance Index (PI) be used to evaluate the relative severity of a contingency 8 [3]. The most common form of system performance 7 indices gives a measure of the deviation from rated values 6 5 of system variables such as line flows, bus voltages, bus p 4 PI power injections, etc. The indices to quantify problems 3 related to loading and voltage limit violations are described 2 1 in equations (1) and (2). 0 e 1) Active power performance index (PIρ): This index is e I e e e used to measure the degree of line over loads and is given by [4].

2n Jimma_Agaro 230kV line Kality I_Akaki I 230kV lin GG II_SekoruGG II_SebetaSebeta II 400kV II_Akaki II 400kV lin 400kV lin lin N   Kality I_Akaki I 230kV line Gefersa_Sebeta II 230kV line 1  W  Pl D/Markos _SulultaKality 400kVB/Dar I_Akaki line SebetaII_D/Markos I 230kV I_Mekanisa line400kV II 132kV line line Legetafo_Ayat GIS 132kV line PI =   AlamataGefersa_Addis _CombolchaCombolcha_Legetafo North 230kV 132kV lin 230kV line line ° ∑ =   max (1) Cotobie _Addis East II 132kV line  i 1 2n  p  Cotobie _Weregenu TP 132kV line  l  Fig. 1 Line outages ranking in terms of PIρ where

Pl – The MW flow of line l Fig. 1 shows the ranking of line outages in terms of max Pl – The MW capacity limit of line l the performance index calculated based on the branches

Nl – The number of overloaded lines in the system overload. It can be seen that the most dangerous line outage W – Real power weighting factor (in general, W = 1) is the disconnection of Debre Markos_Sululta 400 kV line n – A positive number (n = 1, 2, 3… etc...). that leads to an increase in the path of the power supply to The summation is carried out on overloaded lines only the high load centers from Beles hydropower plant. to avoid the masking problem reported in [3], [4], [5]. On the other hand, Fig. 2 shows the line outages 2) Voltage performance index (PIv): The voltage level ranking based on the performance index calculated in terms performance index chosen to quantify system deficiency of bus voltage limit violations. It is found that the most due to out of limit bus voltages in defined by [4]. dangerous line outages from the voltage point of view are  SP 2n the disconnections of lines of Alamata_Combolcha 230 kV, N  Vi − Vi  PIv = B ()w n (2) Akaki I_Kality I 230 kV line I & II, and Sebeta I_Kality I ∑i=1 2  sp   Vi  230 kV lines.

359 Global Energy Interconnection Vol. 1 No. 3 Aug. 2018

data is taken from national load dispatch center (NLDC), power system planning department. At this specific time, 0.12 the system was loaded to 1539.74 MW from which 100 0.1 MW was exported to the Republic of Sudan and 50 MW 0.08 was exported to Djibouti. The full AC power flow is run 0.06 to get the steady state results, such as bus voltages and line 0.04 flows. Next, line outage analysis is done by considering 0.02 a load scaling factor of 1.33, as this factor is used by the 0 planning and operation department of NLDC for daily . I I e e peak load forecasting and generation dispatch scheduling. This data is fed to DIgSILENT PowerFactory software and computer simulation is then performed for each line outage. Gefersa_Sebeta I 230kV GG II_SekoruHurs 400kV o_PK12 line 230kV line Awash II_AselaHurs o_Akaki132kV line INazret 230kVAkaki II_Koka line I_Koka 132kV 230kV line line Simulation of the line outages begins with ascertaining Akaki_KalityAkaki_KalityKality I 230kVI_Sebeta I 230kV line I 230kVline II lin Sebeta II_Akaki 400kV line Akaki I_Koka 230kV line II Alaba_Shashemene 132kV line Alamata_Combolcha 230kV lin GondarGondar II_B/Dar II_B/Dar II 230kV II 230kV line lineI II Adama Wind II_Koka 230kV line Shashemene_Melkawakena yougo.. a steady state solution of the system at base case, and it is obtained that there is overloading of components. Voltage Performance Index (PIv) Moreover, there are no voltage limit violations at the load Fig. 2 Line outages ranking in terms of PIv buses. Next, computer simulation is run for each line outage 3 Result Analysis and discussions and, it is obtained that there are 28 severe line outages whose active power flow performance indices are greater 3.1 Analysis Results for the Most Severe Line Outages than 1.0 pu and voltage level performance indices are The above proposed algorithm is used for the snapshot greater than 0.02 pu. The ends of the transmission lines of the EEP grid at 19:00 on July 17, 2016. At this snapshot, associated with the most severe line outages are labeled the system contained 63 synchronous generators, 104 load in Fig. 3. It is evident that most of these line outages are buses, 134 substations, 99 two-winding transformers, 26 predominantly along the highest voltage transmission lines three-phase transformers, 3 shunt capacitor banks, 45 shunt (400 kV & 230 kV) connecting the regional power systems reactors and 142 transmission lines. The detailed system of the country to the capital, Addis Ababa. Almost all of the

Fig. 3 Portions of the EEP grid showing points of interest

360 Moges Alemu Tikuneh et al. Identification of system vulnerabilities in the Ethiopian electric power system line outages affect the high load centers, i.e., Addis Ababa continue and central regions, as can be seen in Table 1 and Table Loading (in %) Line outage Overloaded 2. This knowledge implies that as far as the transmission Contingency (Name) Component(s) Base case network is concerned, the main weaknesses of the EEP grid loading are on the lines feeding Addis Ababa and Central regions Sebeta I_Mekanisa from the rest of the regional power systems. 164.2 81.4 132 kV line Table 1 and Table 2 show loading and voltage limit violations for the most severe line outages of power system Cotobie_Weregenu 141.9 90.7 elements and buses respectively. TP 132 kV line

Gefersa_Addis Table 1 Loding violations per case 120.3 85.3 Kality I_Akaki I North 132 kV line Loading (in %) 230 kV line I, II Kality I_Akaki I Line outage Overloaded 119.9 96.1 Contingency 132 kV line I, II (Name) Component(s) Base case loading Combolcha 113.4 98.6 Combolcha 230/132 kV Tr. 204.1 98.6 230/132 kV Tr. Gefersa_kality I 109.6 25.6 132 kV line Alamata_ Combolcha 149.7 39.8 D/Markos 400/ 135.7 43.6 230 kV line 230 kV Tr.

Legetafo_Ayat Combolcha 137.6 92.9 109.3 98.6 GIS 132 kV line 230/132 kV Tr.

B/Dar_D/Markos Legetafo_Ayat Cotobie_Ayat GIS 103.0 92.9 137.0 92.3 GIS 132 kV line 132 kV line 400 kV line D/Markos_ Sululta 400 kV Cotobie_Ayat GIS Ghedo 230/132 kV 102.4 92.3 110.9 98.2 132 kV line tr. B/Dar 400/230 kV 100.9 35.2 Combolcha_ Tr. Legetafo 230 kV 107.7 17.2 line Mekanisa_Kality I 110.9 96.1 132 kV line I, II B/Dar 400/230 kV 102.0 35.2 Tr1. Kality I_Akaki I 110.9 96.1 132 kV line I, II B/Dar 400/230 kV 102 35.2 Sebeta I_ Cotobie_ Tr2. Mekanisa 132 kV Weregenu TP 132 103.9 90.7 line kV line Sebeta I_Mekanisa 164.2 81.4 Gefersa_Addis 132 kV line 102.7 85.3 North 132 kV line Cotobie_Weregenu 141.9 90.7 Combolcha TP 132 kV line 101.4 98.6 230/132 kV Tr.

Gefersa_Addis Ghedo 230/132 kV 120.3 85.3 213.7 98.2 North 132 kV line Tr. Kality I_Sebeta I Jimma_Agaro 230 kV line Kality I_Akaki I 230 kV line Sekoru 230/132 kV 119.9 96.1 133.1 72.6 132 kV line I & II Tr.

Combolcha Sululta 400/230 113.4 98.6 117.6 80.7 230/132 kV Tr. Alamata_ kV Tr. Combolcha 230 Gefersa_Kality I kV line Kality I_Akaki I 109.6 25.5 107.4 96.1 132 kV line 132 kV line I, II

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Continue of equipment while overloads could permanently damage Loading (in %) equipment, also leading to instability [3]. Normally, Line outage Overloaded procedures need to be put in place to prevent the system Contingency (Name) Component(s) Base case loading from reaching such an operating point and may require that part of the system get shut down in a coordinated way to Cotobie_Addis 124.4 36.0 save the system from damage, at the cost of interrupting East II 132 kV line supply to some customers. Such type of cutting of supply Kality I_Akaki I 105.0 96.1 to customers results in forced blackouts, and are very 132 kV line I, II Gefersa_Addis common in the Ethiopian electricity sector and have been North 132 kV line Combolcha 104.1 98.6 widely reported by NLDC in [2] and [8], though scientific 230/132 kV Tr. publications are not available. Sebeta I_Mekanisa 101.4 81.4 132 kV line Table 2 Voltage limit violations per case Combolcha 128.7 98.6 Combolcha_ 230/132 kV Tr. Line outage Voltage (p.u) Bus name (s) Legetafo 230 kV (Name) Kality I_Akaki I Actual Base case line 100.1 96.1 132 kV line I, II Akaki I 132 kV 0.90 0.92 Kality I_Weregenu 147.2 52.6 Sululta 230 kV 0.89 0.93 Cotobie_Weregenu TP 132 kV line TP 132 kV Kality I 230 kV 0.89 0.93 Kality I_Akaki I line 105.6 96.1 132 kV line I, II Legetafo 230 kV 0.88 0.92

Gefersa_Addis Sululta 400 kV 0.88 0.93 130.4 85.3 Legetafo_Ayat North 132 kV line Alamata_ Gefersa 132 kV 0.87 0.91 Combolcha 230 kV GIS 132 kV line Kality I_Akaki I 119.1 96.1 line Kality I 132 kV 0.87 0.90 132 kV line I, II Shehedi 230 kV 0.87 0.90 Gefersa_Addis 129.9 85.3 Sululta 132 kV 0.87 0.91 Cotobie_Addis North 132 kV line East II 132 kV Cotobie_ Combolcha 230 kV 0.82 0.94 line Weregenu TP 104.3 90.7 Combolcha 132 kV 0.81 0.93 132 kV line D/Berhan 132 kV 0.84 0.91 Kality I_Akaki I 109.7 96.1 Kality I 230 kV 0.89 0.93 Gefersa_Sebeta I 132 kV line I, II 230 kV line Combolcha Legetafo 230 kV 0.89 0.92 104.7 98.6 230/132 kV Tr. Shashemene 132 kV 0.89 0.92 Sekoru 230/ 106.6 72.6 Debrezeit TP 132 kV 0.88 0.92 G/Gibe II_Sebeta 132 kV Tr. Debrezeit II 132 kV 0.88 0.92 II 400 kV line Combolcha 102.4 98.6 Akaki I 132 kV 0.88 0.92 230/132 kV Tr. Akaki I_Kality I Combolcha 230 kV line I, II Shoarobit 132 kV 0.88 0.91 102.7 98.6 Sebeta II_Akaki I 230/132 kV Tr. Sululta 132 kV 0.87 0.91 400 kV line Kality I_Akaki I 101.7 96.1 Awasa 132 kV 0.87 0.90 132 kV line I, II Gefersa 132 kV 0.87 0.91 Metu 230/66/ 101.5 95.5 D/Berhan 132 kV 0.87 0.91 G/Gibe II_Sekoru 15 kV Tr. 400 kV line Combolcha Kality I 132 kV 0.86 0.90 100.8 98.6 230/132 kV Tr. Kality I 230 kV 0.89 0.93

The result shows several violations as indicated in Table Kality I_Sebeta I Legetafo 230 kV 0.89 0.93 1 & 2. With these violations, it is unlikely that the system 230 kV line Shashemene 132 kV 0.89 0.92 would be able to operate. Voltages outside their limits Debrezeit TP 132 kV 0.89 0.92 could lead to widespread instability, failures, and damage

362 Moges Alemu Tikuneh et al. Identification of system vulnerabilities in the Ethiopian electric power system

Continue Continue

Line outage Voltage (p.u) Line outage Voltage (p.u) Bus name (s) Bus name (s) (Name) Actual Base case (Name) Actual Base case

Debrezeit II 132 kV 0.89 0.92 Shashemene 132 kV 0.89 0.92

Akaki I 132 kV 0.88 0.92 Awash II_Asela Awasa 132 kV 0.87 0.90 Shoarobit 132 kV 0.88 0.91 132 kV line Adamitulu 132 kV 0.86 0.92

Kality I_Sebeta I Sululta 132 kV 0.88 0.91 Assela 132 kV 0.85 0.93 230 kV line Awasa 132 kV 0.87 0.90 Shoarobit 132 kV 0.89 0.91

Gefersa 132 kV 0.87 0.87 0.91 D/Berhan 132 kV 0.89 0.91 Sebeta II_Akaki I D/Berhan 132 kV 0.87 0.91 Sululta 132 kV 0.88 091 400 kV line Kality I 132 kV 0.86 0.90 Gefersa 132 kV 0.88 0.91

Sululta 400 kV 0.89 0.93 Kality I 132 kV 0.88 0.90

Gefersa 230 kV 0.89 0.94 Harar III 132 kV 0.88 0.92 Hurso_Adigala Kality I 132 kV 0.88 0.90 PK12 0.85 0.98 230 kV line Shoarobit 132 kV 0.88 0.91 Adigala 230 kV 0.84 1.0 Sululta 230 kV 0.88 0.93 Gefersa_Sebeta I Gondar II 230 kV 0.89 0.95 230 kV line Kality I 230 kV 0.88 0.93 Gondar II_B/Dar II Gondar II 66 kV 0.88 0.94 230 kV line I. II Legetafo 230 kV 0.88 0.93 Shehedi 230 kV 0.84 0.90 Gefersa 132 kV 0.88 0.93 Koka HPP 132 kV 0.89 0.95 Sululta 132 kV 0.86 0.91 Nazret II_Koka Debrezeit TP 132 kV 0.89 0.93 D/Berhan 132 kV 0.88 0.91 HPP 132 kV line Debrezeit II 132 kV 0.89 0.93 Gambela 230 kV 0.89 0.95 Kality I 132 kV 0.88 0.91 Nekemte 132 kV 0.90 0.94 Kality I 132 kV 0.88 0.90 Sululta 132 kV 0.89 0.91 G/Gibe II_Sekoru Akaki I_Koka Sululta 132 kV 0.89 0.91 Ghimbi 132 kV 0.89 0.93 400 kV line 230 kV line I, II D/Berhan 132 kV 0.89 0.91 Gefersa 132 kV 0.89 0.91 Gefersa 132 kV 0.89 0.91 Metu 66 kV 0.89 0.95 Adamitulu 132 kV 0.90 0.92 Gambela 66 kV 0.85 0.93 Shasheme_ Melkawakena Shashemene 132 kV 0.88 0.92 Akaki I 132 kV 0.90 0.92 Yougo 132 kV line Awasa 132 kV 0.86 0.90 Shoarobit 132 kV 0.89 0.91

Suluta 132 kV 0.89 0.91 Adama wind II_ D/Berhan 132 kV 0.88 0.91 3.2 Determination of Vulnerable Branch Koka 230 kV line Components and Buses Gefersa 132 kV 0.88 0.91

Kality I 132 kV 0.88 0.90 Generally, results of the line outage simulation give

Harar III 132 kV 0.87 0.92 an idea about vulnerable buses whose voltages must be maintained within limits by transmission and substation Adigala 230 kV 0.89 1.0 rehabilitation and upgrading (TSRUP) projects. For Hurso_PK12 230 kV Harar III 132 kV 0.86 0.92 instance, by installing static shunt compensators at high line Harar III 66 kV 0.85 0.90 load buses or by implementing under voltage load shedding PK12 0.82 0.98 (UVLS) protection schemes, voltage instability can be improved. Overloading of lines and/or transformers can Adamitulu 132 kV 0.87 0.92 Alaba_Shashemen be reduced by increasing the capacities the lines and Shashemene 132 kV 0.84 0.92 132 kV line transformers. Awasa 132 kV 0.82 0.90 Network’s vulnerable buses are those buses that have

363 Global Energy Interconnection Vol. 1 No. 3 Aug. 2018 out of limit voltages in case of line outages. Accordingly, Table 3 Vulnerabilities ranked based on number of line the network’s most vulnerable buses are Sululta and outages lead to component overloads Gefersa 132 kV buses in which 11 different line outages Number of Highest cause them to have out of limit bus voltages. The second Overloaded components outages lead to percentage most vulnerable buses are Kality I and D/ Berhan 132 kV overload loading buses where 9 different line outage cases lead them to have Combolcha 230/132 kV Tr. 12 204.1 out of limit bus voltages. Fig. 4 shows the network’s most Kality I_Akaki I line I, II 12 119.9 vulnerable cases ranked based on the number of outages Gefersa_Addis North 132 kV line 6 129.9 that caused voltage limit violations starting from the most Cotobie_Weregenu TP 132 kV vulnerable buses. 5 141.9 line Sebeta I_Mekanisa 132 kV line 4 164.2 12 Gefersa_Kality I 132 kV line 3 109.6 10 Ghedo 230/132 kV Tr. 2 213.7 8

6 Legetafo_Ayat GIS 132 kV line 2 137.6 4 Cotobie Ayat GIS 132 kV line 2 137.0 2 Sekoru 230/132 kV Tr. 2 133.1 0 Alamata_Combolcha 230 kV line 1 149.7 …

PK12 D/Markos 400/230 kV Tr. 1 135.7

Cotobie _Addis East II 132 kV 1 124.4 Kality I 230V bus Sululta 132kV bus

Akaki I 132kV bus line Ghimbi 132kV bus Kality I 132kV bus Gefersa 132kV bus Gefersa 230kV bus Awassa 132kV bus Harar III 132kV bus Legetafo 230kV bus Nekemte 132kV bus Debrezeit 132kV bus D/Berhan 132kV bus Shoarobit 132kV bus Gondar II 230kV bus Shashemene 132kV … Combolcha 132kV bus Combolcha 230kV bus Debrezeit TP 132kV Sululta 400/230 kV Tr1 & Tr2 1 117.6

Number of outages lead to out of limit voltages Combolcha_Legetafo 230 kV line 1 107.7

Fig. 4 Vulnerabilities ranked based on number of outages B/Dar 400/230 kV Tr1 & Tr2 1 102.0 that lead to voltage limit violations of buses Metu 230/66/15 kV Tr. 1 101.5

Similarly, results of line outage analysis can also give us 4 Conclusions an idea about the vulnerable equipment (lines, transformers or generators) whose capacity must be increased by TSRUP This paper mainly describes a framework for identifying to withstand load violations as a result of line outages, the Ethiopian electric power system vulnerabilities, largely and to secure operation during contingencies. Network based on performance indices and supported by power flow vulnerabilities with respect to component’s overloading are and line outage analyses. the lines/transformers which always become overloaded in In the first step, ranking and identification of most case of different line outages. severe line outages are done based on performance indices. Based on the analysis, it is obtained that the network’s With these identified line outages, network vulnerabilities most vulnerable component is the transformer at are evaluated based on: Combolcha II 230/132 kV substation, in which 12 different Numbers of outages that lead to voltage limit violations line outage cases lead this transformer to overload. Table of buses. III shows the network vulnerabilities ranked based on Numbers of outages that lead to overload. number of line outages lead to lines/transformers overload The highest percentage load of components. starting with the most vulnerable component besides each Accordingly, the analysis shows that most of the component’s highest percentage load. network vulnerabilities in respect of bus voltage violations To sum up, as can be seen from Table 3 and Fig. 4, and element overloading are occurred on those buses and most of the network vulnerabilities in respect of voltage elements found at the high load centers. limit violations and loading violations of buses and This paper does not only identify the vulnerable lines, components respectively, are occurred on those buses and transformers and buses but also gives clear technical components either found at the high load centers or they information related to how these vulnerabilities can be are major power flow paths to it. mitigated.

364 Moges Alemu Tikuneh et al. Identification of system vulnerabilities in the Ethiopian electric power system

References In 2013, he joined the Department of Electrical and Computer Engineering, Debre Berhan University, as an Assistant Lecturer, and [1] World Bank Group - International Development Association, in 2017 became a University-Industry Linkage Coordinator at this "International Development Association Project Paper on a university. His current research interests include electrical power Proposed Additional Credit to the Federal Democratic Republic system operation, control and protection; electrical machines and of Ethiopia for the Electricity Network Reinforcement and drives, flexible ac transmission systems, high-voltage dc, and power Expansion Project", World bank, Ethiopia, May 6, 2016 quality. Mr. Moges is a Fellow of Ethiopian Society Electrical [2] National Load Dispatch Centre of Ethiopia, "Partial and Total Engineers (ESEE); the professional association in Ethiopia. He was Blackouts Report" - National Load Dispatch Center, Ethiopian also working as an Electrical Engineer and a supervisor at Ethiopian Electric Power, Ethiopia, EEP, Addis Ababa, 2013-2015 Electric Power Company, Ethiopia. He had taken various trainings [3] Albuyeh F, Bose A, Heath B (1982) Reactive Power about substation equipments installation and maintenance, SDH/ Considerations in Automatic Contingency Selection , IEEE PDH equipment maintenance and configuration, and Telecom Transactions on Power Apparatus and Systems, PAS- power equipments maintenance in Ethiopia and abroad in China. He 101(1):107-112 had also presented his research findings in international scientific [4] Ejebe GC, Irisarri GD, Mokhtari S et al (1996) Methods for conferences. contingency screening and ranking for voltage stability analysis of power systems, IEEE Transactions on Power Systems, Dr. Ing. Getachew Biru Worku obtained 11(1):350-356 his master and Ph.D. degrees in Electrical [5] Ejebe GC, Wollenberg BF (1979) Automatic Contingency Engineering in Dresden Technical University, Selection, IEEE Transactions on Power Apparatus and Systems, Germany. He has more than 25 years of PAS-98(1):97-109 academic and research experience in academic [6] Wood AJ, Wollenberg BF, Sheblé GB (2013) Power Generation, institutions and industry. He has given Operation, and Control, Second Edition, Wiley-Interscience, pp. lectures and advised Postgraduate Students in 415-436 electrical power in Addis Ababa University, [7] Gonzalez-Longatt FM, Rueda JL (2014) PowerFactory Bahir Dar University, in Adama Science Technology University and Applications for Power System Analysis, Stuttgart Und Jimma University. He has served as Dean, Department head and Umgebung, Deutschland: Springer, August 2014 Academic Program Officer in Bahir Dar University and Chairman [8] E. National Load Dispatch Centre, Operating Procedures for of Electrical and Computer Engineering Department in Addis Ababa National Load Dispatch Centre, Addis Ababa, 2015 University. Dr.-Ing. Getachew Biru has also worked in the Ethiopian Aviation Academy. His research areas are electrical power and Biographies renewable energy applications and published more than 13 papers in peer-reviewed International and national journals. Moges Alemu Tikuneh was born in Motta, Ethiopia, in 1990. He received the bachelor (Editor Zhou Zhou) degree in electrical and computer engineering from Jimma University, Jimma, Ethiopia, in 2012, and the master degree in electrical power engineering from Addis Ababa Institute of Technology (AAiT), Addis Ababa, Ethiopia, in 2017.

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