Stability Improvement of The Iraqi Super Grid (400kV) using High Voltage Direct Current (HVDC) Transmission

This research analyzes the level of the short circuit effect of the Iraqi super network and decides the suitable location for the High Voltage Direct Current (HVDC) connections in order to obtain the best short circuit reduction of the total currents of the buses in the network. The proposed method depends on choosing the transmission lines for Alternating current (AC) system that suffers from high Short Circuit Levels (SCLs) in order to reduce its impact on the transmission system and on the lines adjacent to it and this after replacing the alternating current (AC) line by direct current (DC) line. In this paper, Power System Simulator for Engineering (PSS/E) is used to model two types of HVDC lines in an effective region of Iraqi networks and to perform comparative studies to test the location of Short Circuit Levels (SCLs) between an actual AC and AC/DC case study in a portion of the Iraqi national network. The results proved the effectiveness of this method in eliminating severe faults and unwanted short currents, and the results showed that the bipolar type is better in reducing Short Circuit Levels of the Iraqi network.

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A Novel Pilot Protection Principle Based on Modulus Traveling-Wave Currents for Voltage-Sourced Converter Based High Voltage Direct Current (VSC-HVDC) Transmission Lines

Energies ◽

10.3390/en11092395 ◽

2018 ◽

Vol 11 (9) ◽

pp. 2395 ◽

Cited By ~ 4

Author(s):

Xiangyu Pei ◽

Guangfu Tang ◽

Shengmei Zhang

Keyword(s):

High Voltage ◽

Direct Current ◽

Transmission Lines ◽

Traveling Wave ◽

Hvdc Transmission ◽

High Voltage Direct Current ◽

Hvdc Transmission Lines ◽

Dc Line ◽

Voltage Sourced Converter ◽

Pilot Protection

Protection for transmission lines is one of crucial problems that urgently to be solved in constructing the future high-voltage and large-capacity voltage-sourced converter based high voltage direct current (VSC-HVDC) systems. In order to prevent the DC line fault from deteriorating further due to the failure of main protection, a novel pilot protection principle for VSC-HVDC transmission lines is proposed in this paper. The proposed protection principle is based on characteristics of modulus traveling-wave (TW) currents. Firstly, the protection starting-up criterion is constructed by using the absolute value of the 1-mode TW current gradient. Secondly, the fault section identification is realized by comparing the polarities of wavelet transform modulus maxima (WTMM) of 1-mode initial TW currents acquired from both terminals of the DC line. Then, the selection of fault line is actualized according to the polarity of WTMM of local 0-mode initial reverse TW current. A four-terminal VSC-based DC grid electromagnetic transient model based on the actual engineering parameters is built to assess the performance of the proposed pilot protection principle. Simulation results for different cases prove that the proposed pilot protection principle is excellent in reliability, selectivity, and robustness. Moreover, the data synchronization is not required seriously. Therefore, the proposed novel pilot protection principle can be used as a relatively perfect backup protection for VSC-HVDC transmission lines.

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A Study for the Measurement of the Minimum Clearance Distance between the 500 kV DC Transmission Line and Vegetation

Energies ◽

10.3390/en11102606 ◽

2018 ◽

Vol 11 (10) ◽

pp. 2606

Author(s):

Kumail Kharal ◽

Chang-Hwan Kim ◽

Chulwon Park ◽

Jae-Hyun Lee ◽

Chang-Gi Park ◽

...

Keyword(s):

High Voltage ◽

Transmission Lines ◽

Power Transmission ◽

Electrical Power ◽

Long Distance ◽

Dc Voltage ◽

Hvdc Transmission ◽

High Voltage Direct Current ◽

Dc Line ◽

Pass Through

High voltage direct current (HVDC) transmission is being widely implemented for long-distance electrical power transmission due to its specific benefits over high voltage alternating current (HVAC) transmission. Most transmission lines pass through forests. Around the HVDC lines, an arc to a nearby tree may be produced. Thus, there should be a minimum possible clearance distance between a live conductor and a nearby tree, named the minimum vegetation clearance distance (MVCD), to avoid short-circuiting. Measurement of minimum clearance distance between the conductor and trees is a significant challenge for a transmission system. In the case of HVAC transmission, a large amount of research has been undertaken in the form of the Gallet equation for the measurement of this distance, whereas for HVDC transmission no substantial work has been done. An equivalent AC voltage value can be derived from the DC voltage value in order to use the Gallet equation. This paper presents an experimental measurement technique for determining the MVCD at 500 kV to verify the results obtained from the Gallet equation in the case of DC voltage. Performing the experiment with a 500 kV DC line is not possible in the laboratory due to safety concerns. Therefore, an experiment up to 60 kV is conducted to measure the MVCD for DC voltage. The measured results achieved from the experiment are then extrapolated to calculate the MVCD at 500 kV.

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Optimal transmission conversion from alternating current to high voltage direct current transmission systems for limiting short circuit currents

Energy ◽

10.1016/j.energy.2016.10.071 ◽

2017 ◽

Vol 118 ◽

pp. 545-555 ◽

Cited By ~ 1

Author(s):

Jianxiao Wang ◽

Haiwang Zhong ◽

Qing Xia ◽

Chongqing Kang

Keyword(s):

High Voltage ◽

Direct Current ◽

Short Circuit ◽

Alternating Current ◽

Transmission Systems ◽

High Voltage Direct Current ◽

Current Transmission ◽

Short Circuit Currents

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Global experience of HVDC composite insulators in outdoor and indoor environment

REVIEWS ON ADVANCED MATERIALS SCIENCE ◽

10.1515/rams-2020-0050 ◽

2020 ◽

Vol 59 (1) ◽

pp. 606-618

Author(s):

Mohammad Akbar ◽

Basharat Mehmood

Keyword(s):

High Voltage ◽

Direct Current ◽

Transmission Lines ◽

Power Transmission ◽

Green Energy ◽

Attractive Alternative ◽

Hvdc Transmission ◽

Ceramic Insulators ◽

High Power Transmission ◽

Aging Performance

AbstractHigh-voltage direct current (HVDC) transmission is known as green-energy transfer technology and has recently become an attractive alternative of high-voltage alternating current (HVAC) due to its high-power transmission capability and lower power loss. Use of composite insulators on direct current (DC) transmission lines experienced rapid growth in recent years due to their high hydrophobicity and better performance in contaminated environment than conventional ceramic insulators. During their service operation on DC lines, insulators are prone to more accumulation of contaminants due to unidirectional electric field. The contaminants under wet conditions allow leakage current to flow on the insulator surface. Being organic in nature, polymeric insulators have a tendency to age under the combined effects of electrical and environmental stresses. To fully understand the long-term aging performance of DC composite insulators, a detailed survey was considered necessary. Towards that end, this paper critically summarizes worldwide experience of aging performance of composite insulators in the field as well as in laboratory conditions.

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