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Conventional load flow algorithms are very commonly used in the system planning. In the conventional load flow methods, system electrical parameters at specific weather conditions will be considered. These methods gives results for given loading condition and have no provision to incorporate weather condition of a specific geographical location. If the load flow has the provision to incorporate the dynamic electrical characteristics of the conductors based on the operating weather condition, the results of the methods are going to be more accurate or in other words the results are close to the real values. In view of the above, in this paper a modified load flow algorithm incorporating the thermal modeling of the conductors with ambient temperature, wind velocity, conductor surface absorptivity, global solar radiation, Wind direction factor etc. is proposed. To verify the effectiveness of the proposed algorithm, the thermal mathematical model of transmission lines available in IEEE Std. 738™ -2006, IEEE Std. 738™ -2012 and CIGRE WG 22.12 are considered. In the proposed algorithm, new variables corresponding to Conductor Temperature are incorporated. The proposed algorithm is tested with the real time weather data of India and demonstrated on IEEE 30 and 118 bus systems. • An algorithm for power flow including thermal models of the transmission lines. • Variable weather and ZIP load models are incorporated in the proposed algorithm. • It estimates the transmission line temperature using the field measurements. • Seasonal variations of the critical bus voltages are estimated using proposed method. • Impact of renewable generation on system performance is evaluated. [ABSTRACT FROM AUTHOR]

In this paper, an optimal off-grid solar photovoltaic (PV)/hydrogen fuel cell (FC) (HFC) based energy system is proposed for renewable energy generation to supply electricity to the end-user load demand in north-east (NE) Indian states. The energy system is modeled and simulated in the HOMER software. The monthly average global horizontal solar radiation (GHSR) and ambient temperature of the NE states are found to be 3.95–4.79 kWh/m2 and 12.9–25.3 °C, respectively. The synthesized typical AC electrical load profile of 10 kWp is assumed to have a scaled daily annual mean value equal to 138 kWh/d and an average base demand value equal to 5.75 kW. With the considered connected load, the available GHSR and ambient temperature, the optimal sizes of renewable energy components for the considered eight geographical locations (latitude: 23° 30′-27° 3′ North, longitude: 88° 37' – 94° 7′ East) are determined based on the minimum levelized cost of energy (COE) and lowest net present cost (NPC). The optimal system architecture range obtained is 110–120 kW PV array, 10–15 kW FC, 30–60 kW electrolyzer, 40–60 kg hydrogen tank capacity and 15 kW converter. Based on optimization results, the levelized COE and NPC range obtained are 0.509–0.689 $/kWh and $ 3,27,557–4,43,004, respectively, which confirm the cost-effectiveness of the proposed optimal energy system. Besides, with a renewable fraction of 100%, the electricity generated by the PV/HFC system satisfied the load demand and produced excess electricity with capacity factor found to be 16.4–31.2% in all the NE Indian states. Moreover, the optimized electrical profile, PV profile, inverter profile, and hydrogen production from an FC are compared and analyzed in terms of monthly average and annualized values for all the NE states. Also, the range of net hydrogen produced by the electrolyzer over the year obtained is 1538–1856 kg/yr. [Display omitted] • Recommended an optimal off-grid PV/HFC energy systems for eight India north east (NE) states. • System profiles are compared, analyzed and discussed for all the NE states. • The levelized COE is 0.509 – 0.689 $/kWh and NPC is $ 3, 27,557-4, 43,004. • Excess electricity produced in NE states ranges from 21.4-41.4%. • Net hydrogen produced by the electrolyzer over the year is obtained as1538-1856 kg/yr. [ABSTRACT FROM AUTHOR]