Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 977 https://internationalpubls.com Improving Distribution System Performance using the Optimal Placement of DGs and Reconfiguration for Different Load Models Ravi Kant Yadav1 , Dibya Bharti2 , Mala De3 1 (PhD Scholar), Department of Electrical Engineering, National Institute of Technology, Patna, India, raviy.phd19.ee@nitp.ac.in 2Assistant professor, Department of electrical engineering, Bhagalpur college of engineering, Bhagalpur, Bihar 813210, dibya_minu1@rediffmail.com 3Associate professor, Department of Electrical Engineering, National Institute of Technology, Patna, India, mala@nitp.ac.in Article History: Received: 12-11-2024 Revised: 10-12-2024 Accepted: 15-01-2025 Abstract: The distribution system often gets significant power losses due to voltage drops. To address this issue, various techniques have been proposed in the literature, predominantly focusing on single-load models. This study introduces a methodology aimed to minimizing system losses and enhancing voltage profiles by integrating distributed generation (DG) placement with network reconfiguration (NR) for different load models. The analysis considers constant power (CP), constant current (CI), constant impedance (CZ), and constant impedance, current and power (ZIP) load models under varying load conditions. The methodology employs the index vector approach and a modified whale optimization algorithm to identify the optimal placement of DGs. A load escalation rate of 7% is factored in for planning the distribution system over a five-year. The approach is validated using modified 33-bus and 69-bus radial distribution systems (RDS), with performance com- pared against genetic algorithm (GA) and particle swarm optimization (PSO) techniques for the Constant power load model. The results indicate that combining system reconfiguration with DG placement effectively reduces system losses while enhancing voltage stability. Keywords: Radial distribution system (RDS), Modified whale optimization algorithm (MWOA), Constant power load model (CPLM), Constant current load model (CCLM), Constant impedance load model (CILM), and Constant impedance, current and power load model (ZIPLM). 1 Introduction Managing and controlling of distribution networks becomes more complex with fluctuating load demand, particularly in areas with high load density. Fixed network topologies, combined with varying load demands, often lead to significant power losses in RDS, posing challenges for operators. Techniques such as optimal distributed generation placement (ODGP) and network reconfiguration (NR) are widely utilized to address these issues. NR involves modifying the configuration of feeders by adjusting the operational states of sectionalizing and tie switches. DGs are small-scale power generation units, varying from a few kW to MW, directly integrated into the current distribution networks. This reconfiguration approach is nonlinear in nature and helps alleviate overloaded feeders, thereby reducing system losses. mailto:raviy.phd19.ee@nitp.ac.in mailto:dibya_minu1@rediffmail.com mailto:mala@nitp.ac.in Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 978 https://internationalpubls.com Researchers have explored the use of DGs with different load models, as well as employing series voltage regulators and shunt capacitors, to maintain voltage levels and minimize losses in distribution systems. However, shunt capacitors and series voltage regulators have limitations. Shunt capacitors cannot provide continuously adjustable reactive power, and series voltage regulators operate slowly due to their stepwise adjustments. Strategically placing DGs with different load models in distribution systems (DS) offers an effective solution for improving system performance and addressing the limitations of constant load models, shunt capacitors, and series voltage regulators. 1.1 Concepts and motivations Renewable energy has been growing rapidly due to increasing concern for environmental sustainability and the wide adaption of EVs in transport sector. As a result, the integration of DGs and EV charging stations has become a critical area of research in the field of power systems. The optimal placement of DGs and reconfiguration can significantly improve the performance of the distribution system. This study aims to address these challenges by proposing a comprehensive framework for the optimal integration of DG placement and reconfiguration of DS. In this study, propose the minimization of distribution system power losses, improvement of the voltage profile. The different load models taking into the optimization model, the placement of DG and reconfiguration can be effectively optimized to enhance the overall performance of the distribution system. Moreover, the proposed framework con- siders the dynamic nature of load, ensuring that the optimal placement and allocation are robust under varying load conditions. Additionally, the varying load profiles are accounted for to ensure that the distribution system can accommodate different demand scenarios, leading to improved reliability and efficiency [6]. 1.2 Existing Work: Various strategies have been proposed in the literature to address the problem of distribution system reconfiguration (DSR) for minimizing power losses. One heuristic method focuses on network recon- figuration to achieve loss reduction [1]. Recent advancements include the chaotic stochastic fractal search algorithm (CSFSA), which integrates chaotic behavior into the traditional stochastic fractal search algorithm (SFSA) to enhance distribution system reconfiguration performance [2]. Several approaches have also been introduced for solving the DG allocation problem. For instance, one method utilizes the whale optimization algorithm to optimize DG placement and sizing, aiming to reduce losses, improve voltage profiles, and enhance reliability while considering residential, commercial, and industrial loads [3]. Another study presents a strategy for placing D-STATCOMs with and without NR for various load models, including CPLM, CILM, CZLM, and ZIPLM, under load variation conditions [4]. The salp swarm algorithm has been applied to concurrently address NR and DG allocation, demonstrating effectiveness in minimizing power loss and voltage deviation under different scenarios, such as isolated DG placement, isolated NR, and NR post-DG placement [5]. Another innovative approach leverages the artificial ecosystem optimizer to integrate DG and capacitor allocation for recon- figuring power distribution systems, with practical application demonstrated on Egypt's 59-bus Cairo distribution system [6]. Additionally, efficient techniques have been developed to simultaneously optimize system reconfiguration and DG placement. These methods aim to minimize power loss, improve voltage profiles, balance loads and feeders, and minimize switching Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 979 https://internationalpubls.com operations. For example, an improved moth swarm algorithm has been employed for test systems with 33 and 84 nodes, achieving multiple objectives effectively [7,8,9]. In [10], the authors discussed distribution NR and DG placement for minimizing power losses and optimizing voltage in DS via the WOA and evaluated its effectiveness on 33-bus and 69-bus grids. A multi objective approach for NR and DG allocation in DS, aiming to minimize losses and operational costs while maximizing stability, was presented in [11]. When the TFN is used to model load uncertainty, the multi objective hybrid big bangโ€“big crunch (MOHBB-BC) method generates diverse Pareto solutions, considering realistic scenarios despite greater losses. The authors of [12] addressed optimal DG allocation, used a hybrid gray wolf optimizer that was applied to various DSs, markedly reduced losses, enhanced voltage profiles without algorithm tuning, outperformed other methods and identified global optimal solutions. Multi objective strategy that integrates NR with DG allocation, and uses evolutionary techniques based on Pareto optimality and fuzzy set theory to achieve optimal configurations across multiple criteria was introduced in [13]. Paper [14] proposed a simultaneous approach and combined NR and capacitor placement in radial distribution networks, employing Johnson's algorithm and an adaptive whale optimization algorithm, which is more efficient than the previous methods in the literature. In [15,16], the authors discussed a genetic algorithm to optimize DG integration, considering electric vehicles (EVs) to reduce power losses and enhance voltage profiles to increase electrical power demand on standard 33- and 69-bus systems under various scenarios. the authors explore the advantages of modern DG technologies compared to traditional power systems, focusing on economic, environmental, and technical aspects. Additionally, it examines various DG technologies that can be integrated into power distribution net- works to achieve enhanced loss reduction [17,18]. The impact of DG penetration levels on active and reactive power losses, voltage profiles, and node voltage deviations across various load types will be analyzed [19,20]. A comprehensive discussion on energy and power losses is included [21,22]. The DG units help manage PEV charging impacts on distribution systems, along with addressing uncertainties in renewable energy, PEV behavior, and time-varying loads, while analyzing reliability through power interruption metrics [23]. Most studies have primarily focused on either distributed generation (DG) allocation or NR to improve the performance of distribution systems (DS). Only a limited number of researchers have explored the simultaneous implementation of NR and DG allocation in distribution networks. A review of the literature reveals that many studies model systems using single load models, despite the fact that real-world power systems exhibit varying load characteristics. In practical scenarios, loads can be represented as CPLM, CILM, CZLM, ZIPLM with load variations. To address these challenges, this study proposes a methodology that integrates optimal placement of DGs and reconfiguration in radial distribution systems (RDS) while considering different load models. 1.3 Novelties of Paper This paper proposes a novel methodology for optimal placement of DGs and reconfiguration, addressing CPLM, CILM, CZLM, and ZIPLM under varying load. This studies have focused on the synergies among renewable energy generation, reconfiguration, and distribution system operation. This research can maximize the utilization of DG resources, minimize grid congestion, and promote the efficient integration of electric vehicles into the transportation and energy sectors. This integrated approach contributes to overall system resilience, sustainability, and cost-effectiveness. Novel optimization techniques have emerged to address multiple conflicting objectives Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 980 https://internationalpubls.com simultaneously. These objectives may include minimizing real power losses, improving the voltage profile, reducing greenhouse gas emissions, and enhancing grid reliability. 1.4 This Paper's Contributions This paper proposes a methodology to minimize system losses and enhance voltage profiles by integrating DG placement with subsequent NR for various load models. The approach focuses on reducing active and reactive power losses through reconfiguration after optimally placing DGs in RDS to improve voltage profiles. The effectiveness of the proposed method is demonstrated using modified 33- bus and 69-bus RDSs with high DG penetration, considering different load models. Numerical results validate the improvements in voltage deviation and the reduction of total power losses achieved by this approach. The proposed methodology is compared against existing techniques, such as the GA and particle PSO, for different load model scenarios, including modified 33-bus RDSs. 1.5 Organization of paper This paper is structured as, Section 2 outlines the formulation of the problem statement for presented approach and methodology, focusing on minimizing voltage deviation and minimizing system losses. In Section 3, To evaluate the performance of the formulated approach, it is applied to a modified 33- bus RDS and a modified 69-bus RDS under various operational scenarios, incorporating multiple DGs. Section 4 presents the results and their analysis for these systems. Section 5 provides a comparative evaluation of the proposed approach with existing methods, including particle PSO and the GA, specifically for the CP load model on the modified 33-bus RDS. Finally, Section 6 concludes the paper by summarizing the key findings. 2 Problem Formulation The proposed methodology aims to minimize active power losses in the DS by combining optimal DG placement with NR, considering CPLM, CILM, CZLM, and ZIPLMs. The index vector method is utilized to identify the optimal DG location, while the modified whale optimization algorithm (MWOA) is applied to determine the optimal DG size. Additionally, the MWOA is employed for NR to further enhance system performance. In distribution systems, lower voltage levels lead to greater power losses compared to transmission systems, primarily due to higher current flows and the comparatively higher resistance of distribution lines, and this is computed as ๐‘ƒ๐‘™๐‘œ๐‘ ๐‘  =โˆ‘ ๐ผ๐‘– 2๐‘› ๐‘– ๐‘…๐‘– The aim of this paper is to minimize active power loss. Therefore, the objective function for the proposed methodology is as follows: ๐น = (๐‘ƒ๐‘™ ) = ๐‘€๐‘–๐‘› โˆ‘ ๐ผ๐‘– 2๐‘› ๐‘– ๐‘…๐‘– (1) This paper aims to reduce active power losses, where the current is denoted by ๐ผ๐‘–, ๐‘…๐‘– represents the resistance, and n signifies the number of buses in power the system. The constraints are Bus Voltage: 0.95 โ‰ค ๐‘‰๐‘– โ‰ค 1.05 Power balance: Pg + โˆ‘ Pdg = Pd + Ploss N k=1 Maximum and minimum limits of DG: 50 โ‰ค ๐‘ƒ๐‘‘๐‘” โ‰ค 2500 Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 981 https://internationalpubls.com DG type I is assigned to the kW limit, DG type II to the kVAR limit, and DG type III to the kVA limit. 2.2. Electrical Load Modeling: In the case of static load models, the real and reactive power can be expressed using an exponential relationship as follows: ๐‘ƒ = ๐‘ƒ0( ๐‘‰ ๐‘‰0 )๐พ๐‘ (2) ๐‘„ = ๐‘„0( ๐‘‰ ๐‘‰0 )๐พ๐‘ž (3) At the nominal voltage ๐‘‰0 of the bus, the active power is denoted as ๐‘ƒ0 and the reactive power as ๐‘„0. The bus load voltage is V, and the load exponents are ๐พ๐‘and ๐พ๐‘ž [4]. For the CPLM, ๐พ๐‘= ๐พ๐‘ž=0. For the CILM,๐พ๐‘= ๐พ๐‘ž=1. For the CZLM, ๐พ๐‘= ๐พ๐‘ž=2. ๐‘ƒ = ๐‘ƒ0[๐›ผ๐‘( ๐‘‰ ๐‘‰0 )2] + ๐›ฝ๐‘( ๐‘‰ ๐‘‰0 ) + ๐›พ๐‘] (4) ๐‘„ = ๐‘„0[๐›ผ๐‘ž( ๐‘‰ ๐‘‰0 )2] + ๐›ฝ๐‘ž( ๐‘‰ ๐‘‰0 ) + ๐›พ๐‘ž] (5) Where ๐›ผ๐‘, ๐›ฝ๐‘, ๐›พ๐‘, ๐›ผ๐‘ž , ๐›ฝ๐‘ž ๐‘Ž๐‘›๐‘‘ ๐›พ๐‘žare ZIPLM coefficients. The sum of the coefficients for the ZIPLM for both active (P) and reactive (Q) power are normalized to 1. ๐›ผ๐‘+ ๐›ฝ๐‘+ ๐›พ๐‘ = 1, ๐›ผ๐‘ž + ๐›ฝ๐‘ž+ ๐›พ๐‘ž= 1. For the suggested methodology, ๐›ผ๐‘= ๐›ผ๐‘ž= 0.1, ๐›ฝ๐‘= ๐›ฝ๐‘ž= 0.1, ๐›พ๐‘= ๐›พ๐‘ž= 0.8. ๐‘ƒ0 represents the real power consumed at a reference voltage ๐‘‰0 and ๐‘„0 represents reactive power consumed at the reference voltage. 2.2.1 Load variation model. - ๐ฟ๐‘œ๐‘Ž๐‘‘๐‘ก = ๐ฟ๐‘œ๐‘Ž๐‘‘0 ร— (1 + ๐‘ฆ) (6) In the 33-bus test system, y represents the annual growth rate, and t denotes the time period during which the feeder supports the load, and ๐‘ฆ = 0.07 and ๐‘ก = 5 year. 2.2.2 Vector Indexing Technique [4] - The vector-based indexing technique [3] can be utilized to identify the best DG placements. For bus n, the corresponding index vector is defined as ๐ผ๐‘›๐‘‘๐‘’๐‘ฅ[๐‘›] = 1 ๐‘‰2[๐‘›] + ๐ผ๐‘ž (๐พ) ๐ผ๐‘ (๐‘˜) ๐‘„๐‘’๐‘“๐‘“[๐‘›] ๐‘„๐‘‡๐‘œ๐‘ก๐‘Ž๐‘™(๐‘›) (7) In the kth branch, ๐ผ๐‘ž (๐พ) corresponds to the real part of the current, while ๐ผ๐‘ (๐‘˜) represents the imaginary part. The reactive load and voltage at the nth bus are denoted as ๐‘„๐‘’๐‘“๐‘“[๐‘›] and ๐‘‰[๐‘›] respectively, whereas ๐‘„๐‘‡๐‘œ๐‘ก๐‘Ž๐‘™(๐‘›) signifies the overall reactive load at that bus. 2.3. MWOA The proposed method uses the modified whale optimization algorithm, which is derived from WOA, a new metaheuristic method inspired by the cooperative behavior of humpback whales. When tested on 29 math problems and 6 structural design challenges, the WOA shows strong performance compared with other modern algorithms and conventional approaches [16]. The mathematical framework of the WOA encompasses processes such as encircling the prey, employing the bubble-net Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 982 https://internationalpubls.com hunting strategy, and searching for prey. These steps are detailed below: 2.3.1. Encapsulating prey - In WOA, the target prey denotes the best available solution. Other agents strive to enhance their positions to achieve the status of the best search agent. The behavioral model is illustrated below: ๐‘‹โƒ— (๐‘ก+1) =๐‘‹โƒ— โˆ—(๐‘ก)โˆ’๐‘ˆโƒ— . ๐‘โƒ— (8) ๐‘โƒ— = [๐‘Š. ๐‘‹โƒ—โˆ—๐‘กโˆ’ ๐‘‹โƒ—. ๐‘ก] (9) ๐‘ˆโƒ— = 2. ๐‘Ž . ๐‘Ÿโƒ— โˆ’ ๐‘Ž (10) ๐‘Š = 2. ๐‘Ÿโƒ— (11) Where ๐‘‹โƒ— โˆ— represents the best solution, X denotes the position vector, Z is a random variable influencing the update, t indicates the current iteration, ๐‘ˆโƒ— and ๐‘Š are coefficient vectors, ๐‘Ž is a diminishing factor with values ranging from 2 to 0, and ๐‘Ÿโƒ— is a randomly selected vector within the range [0, 1] 2.3.2. Bubble net foraging method โ€“ This paper presents two methods for hunting. a. Contracting encircling of the prey: Here, a is a vector within the range [-a, a], with the value of โ€˜aโ€™ decreasing from 2 to 0. In this case, the position U is randomly initialized within the interval [-1, 1]. The new position of โ€˜aโ€™, which is bounded by 0 โ‰ค a โ‰ค 1, is determined between the initial location and the current optimal agent's position in a 2D space, as shown in Equation 8, moving from (X, Y) to (Xโˆ—,Yโˆ—) b. Spiral movement updating - The spiral equation is employed to model the helical movement. X (t + 1) = Z . ๐‘’๐‘๐‘™. cos( 2ฯ€l) + X โˆ— (12) Were as ๐‘’๐‘๐‘™ suggests an exponential component, where b and l are parameters and cos( 2ฯ€l)introduces an oscillatory (periodic) influence. During hunting, whales approaching their prey from two separate directions simultaneously. For the next two methods used to update the positions of the whales, having a 50% probability is applied to determine which approach will be used. X (t + 1) = { X โˆ— (t) โˆ’ U . Z if p < 0.5 Z โ€ฒ. ๐‘’๐‘๐‘™. cos( 2ฯ€l) + X โˆ— if p โ‰ฅ 0.5 (13) c. Search for prey - Instead of using the most efficient search agent, the global optimal values are revised through a randomly selected search agent. ๐‘โƒ— = [๐‘Š . ๐‘‹โƒ— ๐‘Ÿโƒ— ๐‘Ž ๐‘› ๐‘‘ โˆ’ ๐‘‹โƒ— ] (14) X(t+1)=๐‘‹โƒ— ๐‘Ÿโƒ— ๐‘Ž ๐‘› ๐‘‘ โˆ’U Z (15) ๐‘‹โƒ— ๐‘Ÿโƒ— ๐‘Ž ๐‘› ๐‘‘ is the current iteration's random value. 2.4. DG Placement Optimization: An optimization algorithm is required to determine the optimal locations and capacities of DGs in the DS and TPL and TQL represents total active power and total reactive power. Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 983 https://internationalpubls.com Fig.1. Flow chart of proposed DGs placement. 2.5. Distribution system reconfiguration: MWOA is utilized for NR to reduce system losses and improve the voltage profile. A flowchart depicting the proposed methodology is shown in Fig. 2. Fig.2. Algorithm Flow for Reconfiguration. Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 984 https://internationalpubls.com 3 Implementation of the proposed technique To apply the proposed method, two modified radial distribution systems are considered: 33-bus and a 69-bus, both integrated with multiple DGs units. In the 33-bus system, three solar generation units of 10 kW, 20 kW, and 35 kW are added at buses 6, 21, and 26, respectively, as illustrated in Fig. 3a. Similarly, in the 69-bus system, six solar generation units with capacities of 25.0 kW, 30.0 kW, 20.0 kW, 35.0 kW, 40.0 kW, and 45.0 kW are connected at buses 33, 69, 62, 65, 44, and 46, as shown in Fig. 3b. Fig. 3a. Modified 33-bus RDS Table.1. Load Data and Line Data of modified 33 bus test system Load data specifies the active (P) and reactive (Q) power at each bus and Line data specifies the connection between buses and the impedance (R, X). S. No. From Bus To Bus Load (P) (kW) Load (Q) (kVAR) R (p.u.) X (p.u.) 1 1 2 100 60 0.0922 0.0470 2 2 3 90 40 0.4930 0.2511 3 3 4 120 80 0.3660 0.1864 4 4 5 60 30 0.3811 0.1941 5 5 6 60 20 0.8190 0.7070 6 6 7 200 100 0.1872 0.6188 7 7 8 200 100 0.7114 0.2351 8 8 9 60 20 1.0300 0.7400 9 9 10 60 20 1.0440 0.7400 10 10 11 45 30 0.1966 0.0650 11 11 12 60 35 0.3744 0.1238 12 12 13 60 35 1.4680 1.1550 13 13 14 120 80 0.5416 0.7129 14 14 15 60 10 0.5910 0.5260 15 15 16 60 20 0.7463 0.5450 16 16 17 60 20 1.2890 1.7210 17 17 18 90 40 0.7320 0.5740 Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 985 https://internationalpubls.com 18 18 19 90 40 0.1640 0.1565 19 19 20 90 40 1.5042 1.3554 20 20 21 90 40 0.4095 0.4784 21 21 22 90 40 0.7089 0.9373 22 22 23 90 50 0.4512 0.3083 23 23 24 420 200 0.8980 0.7091 24 24 25 420 200 0.8960 0.7011 25 25 26 60 25 0.2030 0.1034 26 26 27 60 25 0.2842 0.1447 27 27 28 60 25 1.0590 0.9337 28 28 29 120 70 0.8042 0.7006 29 29 30 200 600 0.5075 0.2585 30 30 31 150 70 0.9744 0.9630 31 31 32 210 100 0.3105 0.3619 32 32 33 60 40 0.3410 0.5302 33 8 21 0 0 2.0000 2.0000 34 9 15 0 0 2.0000 2.0000 35 12 22 0 0 2.0000 2.0000 36 18 33 0 0 0.5000 0.5000 37 25 29 0 0 0.5000 0.5000 Fig. 3b. Modified 69-bus RDS In the analyzed system, centralized power generation system is located at bus 1. The total power demand is 3650 kW for the modified 33-bus system and 3771 kW for the modified 69-bus system. Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 986 https://internationalpubls.com Table.2. Load Data and Line Data of modified 69 bus test system Load data specifies the active (P) and reactive (Q) power at each bus and Line data specifies the connection between buses and the impedance (R, X). S. No. From Bus To Bus Load (P) (kW) Load (Q) (kVAR) R (p.u.) X (p.u.) 1 1 2 0 0 0.0005 0.0012 2 2 3 0 0 0.0005 0.0012 3 3 4 0 0 0.0015 0.0036 4 4 5 0 0 0.0251 0.0294 5 5 6 2.6 2.2 0.366 0.1864 6 6 7 40.4 30 0.3811 0.1941 7 7 8 75 54 0.0922 0.047 8 8 9 30 22 0.0493 0.0251 9 9 10 28 19 0.819 0.2707 10 10 11 145 104 0.1872 0.0619 11 11 12 145 104 0.7114 0.2351 12 12 13 8 5 1.03 0.34 13 13 14 8 5.5 1.044 0.345 14 14 15 8 5.5 1.058 0.3496 15 15 16 45.5 30 0.1966 0.065 16 16 17 60 35 0.3744 0.1238 17 17 18 60 35 0.0047 0.0016 18 18 19 0 0 0.3276 0.1083 19 19 20 1 0.6 0.2106 0.069 20 20 21 114 81 0.3416 0.1129 21 21 22 5 3.5 0.014 0.0046 22 22 23 0 0 0.1591 0.0526 23 23 24 28 20 0.3463 0.1145 24 24 25 0 0 0.7488 0.2475 25 25 26 14 10 0.3089 0.1021 26 26 27 14 10 0.1732 0.0572 27 27 28 26 18.6 0.0044 0.0108 28 28 29 26 18.6 0.064 0.1565 29 29 30 0 0 0.3978 0.1315 30 30 31 0 0 0.0702 0.0232 31 31 32 0 0 0.351 0.116 32 32 33 14 10 0.839 0.2816 33 33 34 19.5 14 1.708 0.5646 34 34 35 6 4 1.474 0.4873 35 35 36 26 18.55 0.0044 0.0108 Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 987 https://internationalpubls.com 36 36 37 26 18.55 0.064 0.1565 37 37 38 0 0 0.1053 0.123 38 38 39 24 17 0.0304 0.0355 39 39 40 24 17 0.0018 0.0021 40 40 41 1.2 1 0.7283 0.8509 41 41 42 0 0 0.31 0.3623 42 42 43 6 4.3 0.041 0.0478 43 43 44 0 0 0.0092 0.0116 44 44 45 39.22 26.3 0.1089 0.1373 45 45 46 39.22 26.3 0.0009 0.0012 46 46 47 0 0 0.0034 0.0084 47 47 48 79 56.4 0.0851 0.2083 48 48 49 384.7 274.5 0.2898 0.7091 49 49 50 384.7 274.5 0.0822 0.2011 50 50 51 40.5 28.3 0.0928 0.0473 51 51 52 3.6 2.7 0.3319 0.1114 52 52 53 4.35 3.5 0.174 0.0886 53 53 54 26.4 19 0.203 0.1034 54 54 55 24 17.2 0.2842 0.1447 55 55 56 0 0 0.2813 0.1433 56 56 57 0 0 1.59 0.5337 57 57 58 0 0 0.7837 0.263 58 58 59 100 72 0.3042 0.1006 59 59 60 0 0 0.3861 0.1172 60 60 61 1244 888 0.5075 0.2585 61 61 62 32 23 0.0974 0.0496 62 62 63 0 0 0.145 0.0738 63 63 64 227 162 0.7105 0.3619 64 64 65 59 42 1.041 0.5302 65 65 66 18 13 0.2012 0.0611 66 66 67 18 13 0.0047 0.0014 67 67 68 28 20 0.7394 0.2444 68 68 69 28 20 0.0047 0.0016 69 11 43 0 0 0.5 0.5 70 13 20 0 0 0.5 0.5 Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 988 https://internationalpubls.com 4 Results and Discussion The analysis was performed using MATLAB version 9.0 on a Windows 10 system (Intelยฎ Coreโ„ข i3 Processor, 3.30 GHz, 4 GB RAM). The results were obtained for DG placement, both with and without network reconfiguration, in the modified 33-bus and 69-bus RDS under various load models (CPLM, CILM, CZLM, and ZIPLM). The system's performance, including voltage profiles, power loss, and other metrics, was evaluated across different load models. The following three scenarios were considered for the analysis: ๏‚ท Case 1: Only NR of the RDS. ๏‚ท Case 2: Only DGs placement of the RDS. ๏‚ท Case 3: NR after placement of DGs in the RDS. 4.1 CPLM Analysis for the Modified 33-bus RDS The CPLM for both cases is provided in Table 3. The analysis shows a significant reduction in line loss, which decreases from 198.7791 kW to 23.4077 kW in Case 2. In Case 3, the line loss is further reduced to 19.6848 kW. This reduction in active power loss is achieved by installing a total of six DGs units at the following bus locations and capacities: bus 25 (372 kW), bus 28 (459 kW), bus 32 (500 kW), bus 33 (500 kW), bus 11 (391 kW), and bus 17 (500 kW). Fig. 4 illustrates the improvement in voltage profile in Case 3 compared to Case 2. It also highlights, a slightly higher voltage deviation is observed between buses 17 and 18. Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 989 https://internationalpubls.com Fig. 4. Voltage variation for the CPLM Fig. 5. Voltage variation for the CILM Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 990 https://internationalpubls.com 4.2 CILM Analysis for the Modified 33-bus RDS Table 4 presents the results for the CILM, comparing both cases. The analysis reveals a reduction in line loss from 171.6116 kW to 31.5958 kW in Case 2, and further to 28.1628 kW in Case 3. This reduction in active power loss is achieved by placing six DGs units at the following bus locations and capacities: bus 17 (253 kW), bus 21 (176 kW), bus 25 (465 kW), bus 29 (436 kW), bus 31 (292 kW), and bus 8 (328 kW). Fig. 5 illustrates that the voltage deviation in Case 3 closely follows the trend observed in Case 2. Fig. 6. Voltage profile for CZLM Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 991 https://internationalpubls.com Fig. 7. Voltage profile for ZIPLM 4.3 CZLM Analysis for the Modified 33-bus RDS Table 5 compares the results for the CZLM in both cases. The findings show that line loss decreases from 151.8268 kW to 22.3601 kW in Case 2, and further to 29.2304 kW in Case 3. This reduction in real power loss is achieved by installing six DGs units at the following bus locations and capacities: bus 15 (340 kW), bus 27 (328 kW), bus 29 (287 kW), bus 33 (500 kW), bus 3 (500 kW), and bus 8 (260 kW). Fig. 6 demonstrates that the voltage deviation in Case 3 is lower than in Case 2, indicating that reconfiguration is unnecessary after DG placement. 4.4 ZIPLM Analysis for the Modified 33-bus RDS Table 6 presents the results for the ZIPLM in both cases. The analysis reveals that line loss decreases from 191.6269 kW to 30.817 kW in Case 2, and further reduces to 26.6369 kW in Case 3. This reduction in real power loss is achieved by installing six DGs units at the following bus locations and capacities: bus 5 (270 kW), bus 14 (422 kW), bus 16 (365 kW), bus 29 (500 kW), bus 33 (445 kW), and bus 3 (183 kW). Fig. 7 illustrates that the voltage deviation in Case 3 is improved compared to Case 2. The voltage deviation in Case 3 is improved compared to Case 2, with execution times of 2285.256 seconds for Case 3 and 3.2195 seconds for Case 2. Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 992 https://internationalpubls.com 4.5 CPLM Analysis for the Modified 69-bus RDS Table 7 presents the results for the CPLM in both cases. The analysis shows that line loss decreases from 214.2445 kW to 22.2445 kW in Case 2, and further reduces to 15.427 kW in Case 3. This reduction in real power loss is achieved by installing six DGs units at the following bus locations and capacities: bus 2 (500 kW), bus 63 (500 kW), bus 68 (500 kW), bus 59 (500 kW), bus 61 (500 kW), and bus 11 (500 kW). Fig. 8 illustrates that the voltage profile is significantly lower between buses 11 and 28, and between buses 50 and 64. The voltage deviation in Case 3 is improved compared to Case 2, with execution times of 2285.256 seconds for Case 3 and 3.2195 seconds for Case 2. Fig. 8. Voltage profile for CPLM Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 993 https://internationalpubls.com Fig. 9. Voltage profile for CILM 4.6 CILM Analysis for the Modified 69-bus RDS Table 8 compares the results for the CILM in both cases. The analysis reveals that line loss decreases from 180.67 kW to 11.340 kW in Case 2, and further reduces to 10.960 kW in Case 3. This reduction in real power loss is achieved by installing six DGs units at the following bus locations and capacities: bus 59 (500 kW), bus 62 (500 kW), bus 63 (500 kW), bus 65 (226 kW), bus 69 (173 kW), and bus 19 (500 kW). Fig. 9 illustrates that the voltage deviation in Case 3 follows the trend observed in Case 2. The execution time for Case 2 is 3.2498 seconds, while for Case 3, it is 2078.8749 seconds. 4.7 CZLM Analysis for the Modified 69-bus RDS Table 9 compares the results for the CZLM in both cases. The analysis shows that line loss decreases from 152.87 kW to 8.885 kW in Case 2, and further reduces to 12.322 kW in Case 3. This reduction in real power loss is achieved by installing six DGs units at the following bus locations and capacities: bus 50 (500 kW), bus 59 (499 kW), bus 64 (500 kW), bus 69 (500 kW), bus 61 (500 kW), and bus 22 (210 kW). Fig. 10 illustrates that the voltage deviation in Case 3 is lower than that in Case 2, indicating that reconfiguration is unnecessary after DG placement. Time taken to execute the result for base_case, case2 and case3 is 0.49343 sec, 3.1866 sec and 2298.8618 sec respectively that shows the execution time increasing from base_case to case 3. Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 994 https://internationalpubls.com Fig. 10. Voltage deviations for CZLM Fig. 11. Voltage deviation for ZIPLM 4.8 ZIPLM Analysis for the Modified 69-bus RDS Table 10 presents the results for the ZIP load model in both cases. The analysis reveals that line loss decreases from 204.078 kW to 18.1847 kW in Case 2, and further reduces to 16.732 kW in Case 3. This reduction in real power loss is achieved by installing six DGs units at the following bus locations and capacities: bus 62 (468 kW), bus 63 (500 kW), bus 65 (500 kW), bus 69 (448 kW), bus 44 (243 kW), and bus 18 (496 kW). Fig. 11 illustrates that the voltage deviation in Case 3 is improved com- pared to Case 2. The execution time for Case 2 is 3.2975 seconds, while for Case 3, it is 2321.9955 seconds. Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 995 https://internationalpubls.com 5 Comparison of the proposed methodology with existing methodologies To compare the performance of the proposed technique with existing techniques, PSO and GA are applied to the modified 33-bus RDS using the CPLM for Cases 2 and 3. The results of this comparison are presented in Table 11, and the graphical representation is shown in Fig. 14. In PSO_Case 2, The decrease in active power dissipation and reactive power requirements are 47.990 kW and 41.23 kVAR, respectively, achieved by placing two DGs at bus 25 (822 kW) and bus 7 (1000 kW). In GA_Case 2, the savings are 47.0975 kW for real power and 36.0481 kVAR for reactive power, which result from the placement of two DGs at buses 33 (72 kW) and 10 (722 kW). For MWOA_Case 2 with the CPLM, real and reactive power loss savings of 121.3258 kW and 81.7193 kVAR are achieved, with DGs placed at buses 33 (500 kW and 242.161 kVAR), and at bus 15 (500 kW and 242.161 kVAR). Using the CILM in MWOA_Case 2, savings of 127.726 kW in active power and 86.426 kVAR in reactive power, placing DGs strategically at buses 16 (456 kW and 220.851 kVAR), and at buses 31 (434 kW and 210.196 kVAR). Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 996 https://internationalpubls.com The active and reactive power loss reductions of 132.84 kW and 88.88 kVAR, respectively, are achieved in MWOA_Case 2 with the CZLM. This is accomplished by placing two DGs at buses 17 (463 kW and 224.2411 kVAR) and 33 (375 kW and 181.6208 kVAR). For the ZIPLM in MWOA_Case 2, the savings in real power loss increase to 120.374 kW, while reactive power savings rise to 80.414 kVAR. These savings are realized by placing two DGs at buses 33 (500 kW and 242.160 kVAR) and 18 (460 kW and 222.780 kVAR). Fig. 12 illustrates the voltage profile for Case 2 across different load models. The performance evaluation of the proposed technique compared to existing techniques (PSO_Case 3 and GA_Case 3) for the CPLM on the modified 33-bus RDS is summarized Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 997 https://internationalpubls.com in Table 11. Fig. 12. Voltage profile of case 2 for different load model The results show that in PSO_Case 3, the real power loss is reduced by 78.13 kW and the reactive power by 52.232 kVAR. In GA_Case 3, the reductions are 84.4797 kW for real power loss and 60.0733 kVAR for reactive power. Using WOA_Case 3 for the CPLM, the savings increase to 121.3258 kW for real power loss and 135.855 kW. with savings in reactive power rising from 81.7193 kVAR to 87.4698 kVAR. For MWOA_Case 3 with the CILM, the active power loss savings increase from 127.726 kW to 131.897 kW, while the reactive power savings decrease slightly from 86.426 kVAR to 83.45 kVAR. In MWOA_Case 3 for the CZLM, real power loss decreases from 132.8463 kW to 127.6907 kW, with reactive power savings reduced from 88.8863 kVAR to 80.0506 kVAR. Finally, with the ZIPLM in MWOA_Case 3, the active power loss savings increase from 120.374 kW to 135.569 kW, while the reactive power savings improve from 80.414 kVAR to 84.820 kVAR. Fig. 13 displays the voltage profile for Case 3 across the various load models. Fig. 13. Voltage deviation of case3 for different load model Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 9s (2025) 998 https://internationalpubls.com Fig. 14. Comparison of proposed methodology with existing methodologies in terms of active power saving (kW) and reactive power saving (kVAR) for modified 33 bus system 6 Conclusions In this paper, a methodology for NR after DG placement has been proposed for CP, CI, and CZ load models, along with a ZIP load model considering load variation. The analysis demonstrates that reconfiguration post-DG placement significantly enhances voltage profiles, reduces line losses, and leads to power savings. The findings show that, for the CP and CI load models, the voltage deviation and performance improve after reconfiguration. However, for the CZ load model, reconfiguration after DG placement does not provide additional benefits, indicating that it may not be necessary. The ZIP load model analysis also confirms that the voltage profiles and power savings improve with reconfiguration. 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