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DC faults render hindrance in the flourishment of multi-terminal flexible high voltage DC (MTDC). The fault current rises rapidly, making a sharp peak, however, under a specific fault instance, isolation of the whole network is an impractical solution. For effective reliability of the whole network, rapid and accurate fault detection and selection of faulty pole is mandatory. A fault detection scheme is proposed in this paper to draw transient current harmonics from initial fault current by utilizing Discrete Fourier transform (DFT). Current harmonics employed the fault detection promptly at the converter stations without communication among the MTDC networks. Additionally, the proposed scheme can discriminate internal from external fault by tracking the number of pulse count in a specific interval of the harmonics of the voltage. In this way, the reliability of the protection scheme enhances and escape from the mal-operation of the circuit breaker. For four terminal MTDC transmission network, the simulations are carried out in PSCAD to authenticate the implementation of the proposed scheme and protection units (PU) are utilized for the isolation of faulty part with the combination of hybrid circuit breaker (HCB). A keen analysis of test results authenticated the ability of the proposed scheme to rapidly detect the faults with high precision, along with efficient classification of the nature of faults. Furthermore, consequential results provide a strong evidence for its key role in handling a multitude of MTDC faults.
Muhammad Haroon Nadeem; Xiaodong Zheng; Nengling Tai; Mehr Gul; Moduo Yu; Yangyang He. Non-communication based protection scheme using transient harmonics for multi-terminal HVDC networks. International Journal of Electrical Power & Energy Systems 2020, 127, 106636 .
AMA StyleMuhammad Haroon Nadeem, Xiaodong Zheng, Nengling Tai, Mehr Gul, Moduo Yu, Yangyang He. Non-communication based protection scheme using transient harmonics for multi-terminal HVDC networks. International Journal of Electrical Power & Energy Systems. 2020; 127 ():106636.
Chicago/Turabian StyleMuhammad Haroon Nadeem; Xiaodong Zheng; Nengling Tai; Mehr Gul; Moduo Yu; Yangyang He. 2020. "Non-communication based protection scheme using transient harmonics for multi-terminal HVDC networks." International Journal of Electrical Power & Energy Systems 127, no. : 106636.
The relation between fault current waves and variations of transient current in dc transmission lines (DC-TL) is meticulously investigated under numerous fault conditions. On these grounds, a transient current protection scheme is proposed for modular multi-level converter high voltage dc (MMC-HVDC). By using the wave propagation theory, the transient current distribution over the line can be acquired from current at both ends of DC-TL and fault can be localized from the approximate calculated results. Additionally, the sited fault can be precisely computed in case of internal faults. Two terminal MMC-HVDC model is tested in real-time digital simulator (RTDS) for analyzing the application of the proposed scheme. Comprehensive test results authenticate the promising performance of the proposed scheme. Efficient identification of internal as well as external faults with high accuracy, along with viable adoption for high ground resistance faults, is also a distinguishing feature of this scheme. Moreover, two main parameters; fault resistance and distance of fault that affect the protection scheme performance are also addressed critically.
Xiaodong Zheng; Muhammad Haroon Nadeem; Nengling Tai; Salman Habib; Biqi Wang; Moduo Yu; Yangyang He. A transient current protection and fault location scheme for MMC-HVDC transmission network. International Journal of Electrical Power & Energy Systems 2020, 124, 106348 .
AMA StyleXiaodong Zheng, Muhammad Haroon Nadeem, Nengling Tai, Salman Habib, Biqi Wang, Moduo Yu, Yangyang He. A transient current protection and fault location scheme for MMC-HVDC transmission network. International Journal of Electrical Power & Energy Systems. 2020; 124 ():106348.
Chicago/Turabian StyleXiaodong Zheng; Muhammad Haroon Nadeem; Nengling Tai; Salman Habib; Biqi Wang; Moduo Yu; Yangyang He. 2020. "A transient current protection and fault location scheme for MMC-HVDC transmission network." International Journal of Electrical Power & Energy Systems 124, no. : 106348.
The integration of wind power as an alternative energy source has gotten much attention globally. In this paper, the Weibull distribution model based on different artificial intelligent algorithms and numerical methods is used to evaluate the wind profile. The application of Weibull distribution in wind data assessment can be extensively found, but the methods applied for estimating the parameters still need improvement. Three artificial intelligent algorithms are presented as an alternative method for estimation of Weibull parameters, and an objective function is proposed through the concept of maximum distance metric. Its convergence was proven mathematically through its boundedness for all wind data types. The optimization methods based on the proposed objective function are compared with the conventional numerical approaches for Weibull parameter estimation. Two-year wind data from the site in the southern area of Pakistan has been used to conduct this analysis. Furthermore, this work provides an eloquent way for the selection of a suitable area, evaluation of parameters, and appropriate wind turbine models through real-time data for power production.
Mehr Gul; Nengling Tai; Wentao Huang; Muhammad Haroon Nadeem; Moduo Yu. Evaluation of Wind Energy Potential Using an Optimum Approach based on Maximum Distance Metric. Sustainability 2020, 12, 1999 .
AMA StyleMehr Gul, Nengling Tai, Wentao Huang, Muhammad Haroon Nadeem, Moduo Yu. Evaluation of Wind Energy Potential Using an Optimum Approach based on Maximum Distance Metric. Sustainability. 2020; 12 (5):1999.
Chicago/Turabian StyleMehr Gul; Nengling Tai; Wentao Huang; Muhammad Haroon Nadeem; Moduo Yu. 2020. "Evaluation of Wind Energy Potential Using an Optimum Approach based on Maximum Distance Metric." Sustainability 12, no. 5: 1999.
The southwestern part of Pakistan is still not connected to the national grid, despite its abundance in renewable energy resources. However, this area becomes more important for energy projects due to the development of the deep-sea Gwadar port and the China Pakistan Economic Corridor (CPEC). In this paper, a voltage source converter (VSC) based high voltage DC (HVDC) transmission model is proposed to link this area to the national gird. A two-terminal VSC-HVDC model is used as a case study, in which a two-level converter with standard double-loop control is employed. The proposed model has a capacity of transferring bulk power of 3500 MW at 350 kV from Gwadar to Matiari. Furthermore, the discounted cash flow analysis of VSC-HVDC against the HVAC system shows that the proposed system is economically sustainable. The outcomes of this study reveal that the implementation of this project can bring economic stability and energy security in the southwestern region.
Mehr Gul; Nengling Tai; Wentao Huang; Muhammad Haroon Nadeem; Muhammad Ahmad; Moduo Yu. Technical and Economic Assessment of VSC-HVDC Transmission Model: A Case Study of South-Western Region in Pakistan. Electronics 2019, 8, 1305 .
AMA StyleMehr Gul, Nengling Tai, Wentao Huang, Muhammad Haroon Nadeem, Muhammad Ahmad, Moduo Yu. Technical and Economic Assessment of VSC-HVDC Transmission Model: A Case Study of South-Western Region in Pakistan. Electronics. 2019; 8 (11):1305.
Chicago/Turabian StyleMehr Gul; Nengling Tai; Wentao Huang; Muhammad Haroon Nadeem; Muhammad Ahmad; Moduo Yu. 2019. "Technical and Economic Assessment of VSC-HVDC Transmission Model: A Case Study of South-Western Region in Pakistan." Electronics 8, no. 11: 1305.
Wind power is the fastest growing and environmentally sustainable source of energy among all available renewable energy resources. The primary objective of this paper is to analyze the wind characteristics and power potential at Hyderabad, Southeastern province in Pakistan. Two years of wind speed data measured at 10 m above ground level (AGL) have been considered in this study. The annually, monthly, and seasonal variations in wind speed were analyzed, and minimum, maximum, and average values of recorded wind speeds are presented in this paper. Weibull and Rayleigh distribution functions have been applied to analyze the wind characteristics and evaluate the wind power potential of the proposed site. The Weibull shape k and scale c parameters have been estimated using the Weibull function. The higher values of k showed that the wind speed is steady at the site. The average wind speed was found above 6 m/s throughout the year. The most probable wind speed (Vmp) and maximum carrying energy (VmaxE) wind speed were also calculated using Weibull parameters. Root mean square error (RMSE), the coefficient of determination (R2), and mean bias error (MBE) were computed to ensure the good fit of Weibull distribution function. The annual average wind power and energy densities were estimated at more than 255 W/m2 and 2245 kWh/m2, respectively. The power density calculated by Weibull and Rayleigh functions was compared with that calculated by using measured wind data. The energy output and capacity factor of different commercially available wind turbines (WTs), i.e., power ratings from 0.33 to 2.75 MW, have been calculated. The cost of energy was estimated and ranged from $19.27 to $32.80 per MWh. Wind power potential and economic analysis of the collected data reveals that the site is suitable for developing wind power generation projects to power the local communities.
Mehr Gul; Nengling Tai; Wentao Huang; Muhammad Haroon Nadeem; Moduo Yu. Assessment of Wind Power Potential and Economic Analysis at Hyderabad in Pakistan: Powering to Local Communities Using Wind Power. Sustainability 2019, 11, 1391 .
AMA StyleMehr Gul, Nengling Tai, Wentao Huang, Muhammad Haroon Nadeem, Moduo Yu. Assessment of Wind Power Potential and Economic Analysis at Hyderabad in Pakistan: Powering to Local Communities Using Wind Power. Sustainability. 2019; 11 (5):1391.
Chicago/Turabian StyleMehr Gul; Nengling Tai; Wentao Huang; Muhammad Haroon Nadeem; Moduo Yu. 2019. "Assessment of Wind Power Potential and Economic Analysis at Hyderabad in Pakistan: Powering to Local Communities Using Wind Power." Sustainability 11, no. 5: 1391.
Voltage-source-converter-based multi-terminal high voltage direct current (MTDC) networks are extensively recognized as a viable solution for meeting the increasing demand of electrical energy and escalating penetration of renewable energy sources. DC faults are major limitations to the development of MTDC networks. The analysis of variable constraints has become mandatory in order to develop a reliable protection scheme. This paper contributes in assessing the propagation delay with the analytical approximation in MTDC networks. The propagation delay is analyzed in the time domain by taking only the forward traveling wave into account and considering the initial voltage step of magnitude at the fault position. Numerous simulations were carried out for different parameters and arrangements in Power System Computer Aided Design (PSCAD) to explore the proposed expressions. The results accurately depicted the time development of fault current. The results obtained from the real-time digital simulator (RTDS) confirmed that the proposed approach is capable of evaluating propagation delay in MTDC networks. Moreover, the influence of fault resistance is also taken into account for investigating its effect on the system parameters.
Muhammad Haroon Nadeem; Xiaodong Zheng; Nengling Tai; Mehr Gul; Sohaib Tahir. Analysis of Propagation Delay for Multi-Terminal High Voltage Direct Current Networks Interconnecting the Large-Scale Off-Shore Renewable Energy. Energies 2018, 11, 2115 .
AMA StyleMuhammad Haroon Nadeem, Xiaodong Zheng, Nengling Tai, Mehr Gul, Sohaib Tahir. Analysis of Propagation Delay for Multi-Terminal High Voltage Direct Current Networks Interconnecting the Large-Scale Off-Shore Renewable Energy. Energies. 2018; 11 (8):2115.
Chicago/Turabian StyleMuhammad Haroon Nadeem; Xiaodong Zheng; Nengling Tai; Mehr Gul; Sohaib Tahir. 2018. "Analysis of Propagation Delay for Multi-Terminal High Voltage Direct Current Networks Interconnecting the Large-Scale Off-Shore Renewable Energy." Energies 11, no. 8: 2115.
This paper presents a protection scheme to protect multi-terminal high voltage dc (MTDC) networks for interconnection of renewable energy sources. The proposed scheme detects faults by using the Consecutive Data Window Method (CDWM) and harmonics of the system voltage to avoid maloperation of breakers without communication. Fault location is classified and faulty parts is isolated from the rest of the healthier network by using hybrid circuit breakers (HCBs). Moreover; it also categorises the fault with the help of the voltage drop. The rapid response to isolate the faulty portion in a few milliseconds is primarily considered to enhance the reliability and security of the network. The results of simulations verify the efficient fault detection and isolation for different DC faults and the investigation for the impact of significant parameters of the proposed scheme has been considered. The simulations are performed in PSCAD for four terminal MTDC networks to validate the proposed scheme. The performance is also verified under different fault conditions by using Matlab after computing the data from simulations.
Muhammad Haroon Nadeem; Xiaodong Zheng; Nengling Tai; Mehr Gul. Identification and Isolation of Faults in Multi-terminal High Voltage DC Networks with Hybrid Circuit Breakers. Energies 2018, 11, 1086 .
AMA StyleMuhammad Haroon Nadeem, Xiaodong Zheng, Nengling Tai, Mehr Gul. Identification and Isolation of Faults in Multi-terminal High Voltage DC Networks with Hybrid Circuit Breakers. Energies. 2018; 11 (5):1086.
Chicago/Turabian StyleMuhammad Haroon Nadeem; Xiaodong Zheng; Nengling Tai; Mehr Gul. 2018. "Identification and Isolation of Faults in Multi-terminal High Voltage DC Networks with Hybrid Circuit Breakers." Energies 11, no. 5: 1086.