scholarly journals Liquefied natural gas (LNG) and DC electric power transfer system by cryogenic pipe of superconducting DC power transmission (SCDC)

2021 ◽  
Vol 2088 (1) ◽  
pp. 012019
Author(s):  
Sataro Yamaguchi ◽  
Yury Ivanov ◽  
Linda Sugiyama
Keyword(s):  
Natural Gas ◽  
Transmission Lines ◽  
Power Transmission ◽  
Electrical Power ◽  
Liquefied Natural Gas ◽  
Gas Pipeline ◽  
Long Distance ◽  
Hybrid Energy ◽  
Transport Distance ◽  
Transmission Pipeline

Abstract We propose a hybrid energy transmission pipeline that combines the liquefied natural gas (LNG) cryogenic pipelines and superconducting direct current (DC) electrical power transmission cable system (SCDC). The system design is based on experimental data from the SCDC Ishikari project in Japan and related laboratory experiments. The particular structure of the hybrid cryogenic pipe connects the thermal radiation shield of the pipe that contains the DC high temperature superconducting (HTS) electrical cable to the LNG pipe and significantly reduces the heat leak into the SCDC pipe. Because the specific heat of LNG is higher than that of liquid nitrogen and the LNG transfer rate is quite high, the thermal loss of the SCDC cable becomes only 1/100 that of present-day conventional copper cables, far below the factor 1/10 reduction achievable by a stand-alone SCDC transmission lines. The LNG temperature rises by less than 2 K over a 100 km transport distance, which is negligible in actual use. LNG also saves significantly on pumping power compared to a natural gas pipeline. To liquefy the LNG at cryogenic temperature from natural gas at ambient temperature requires a large refrigerator that consumes enormous power. The gas pipeline, however, needs a compressor to produce high-pressure gas, which also consumes a massive amount of power. Due to these considerations, the proposed hybrid system is a viable design for the long-distance joint transportation of LNG and electricity.

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

Energies ◽  
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.

scholarly journals Corona Loss Minimization on High Voltage Transmission Line Network using Bundled Conductors.

2020 ◽  
Vol 9 (3) ◽  
pp. 887-891
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Power Transmission ◽  
Hessian Matrix ◽  
Electrical Power ◽  
Power Transmission Lines ◽  
Long Distance ◽  
Power Stations ◽  
Line Network ◽  
Corona Losses

Electrical power generated and transmitted at a long distance away from the power stations is usually affected by inherent transmission line losses. The Ohmic and Corona losses which are predominantly common in power transmission lines are considered in this paper. These two losses are mathematically modeled with and without embedded bundled conductors. The resultant model which is a non-linear multivariable unconstrained optimized equation is minimized using the Hessian matrix determinant method for stability test purposes. The results obtained show that corona losses are minimized with embedded bundled conductors at a very low current value with large spacing distance between the bundled conductors. The decrease in the corona loss which is a consequence of spacing adjustment of the 2, 3, and 4 strands of bundled conductors was plotted using MATLAB 7.14. The plots obtained are in conformity with the inverse relation between corona loss and conductor spacing.

scholarly journals Data Analysis and Model Validation of Natural Gas Transmission Pipeline With Compressor Station

2019 ◽  
Author(s):  
David Cheng
Keyword(s):  
Performance Analysis ◽  
Natural Gas ◽  
Model Validation ◽  
Measurement Data ◽  
Real Life ◽  
Gas Pipeline ◽  
Physical Parameters ◽  
Pressure Drops ◽  
Natural Gas Transmission ◽  
Transmission Pipeline

Abstract Data from the DCS systems provides important information about the performance and transportation efficiency of a gas pipeline with compressor stations. The pipeline performance data provides correction factors for compressors as part of the operation optimization of natural gas transmission pipelines. This paper presents methods, procedure, and a real life example of model validation based performance analysis of gas pipeline. Statistic methods are demonstrated with real gas pipeline measurement data. The methods offer practical ways to validate the pipeline hydraulics model using the DCS data. The validated models are then used as performance analysis tools in evaluating the fundamental physical parameters and assessing the pipeline hydraulics conditions for potential issues influencing pressure drops in the pipeline such as corrosion (ID change), roughness changes, or BSW deposition.

scholarly journals An Optimized Coordination Strategy between Line Main Protection and Hybrid DC Breakers for VSC-Based DC Grids Using Overhead Transmission Lines

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1462 ◽  
Author(s):  
Zheng ◽  
Jia ◽  
Gong ◽  
Zhang ◽  
Pei
Keyword(s):  
Transmission Lines ◽  
Power Transmission ◽  
Short Circuit ◽  
Power Grids ◽  
Fault Line ◽  
Long Distance ◽  
Coordination Strategy ◽  
Overhead Transmission Lines ◽  
Depth Analysis ◽  
Dc Breaker

Compared with alternating current (AC) power grids, the voltage-sourced converter (VSC)-based direct current (DC) grid is a system characterized by “low damping”, as a result, once there is a short-circuit fault on the DC transmission line, the fault current will rise more sharply and the influence range will be much wider within the same time scale. Moreover the phenomenon that a local fault causes a whole power grid outage is more likely to occur. Overhead transmission lines (OHLs) have been regarded as the mainstream form of power transmission in future high-voltage, large-capacity and long-distance VSC-based DC grids. However, the application of overhead transmission lines will inevitably lead to a great increase in the probability of DC line failure. Therefore, research on how to isolate the DC fault line quickly is of great significance. Based on the technology route for fault line isolation using DC breakers, on the basis of in-depth analysis of traditional coordination strategy, an optimized coordination strategy between line main protection and a hybrid DC breaker for VSC-based DC grids using overhead transmission lines is proposed in this paper, which takes the start-up output signal of line main protection as the pre-operation instruction of the corresponding hybrid DC breaker. As a result, the risks of blockage of the modular multilevel converter (MMC) closer to the fault position and of damage to power electronic devices in main equipment can be reduced effectively. Finally, the proposed coordination strategy was verified and analyzed through simulation.

Design and Implementation of the Airborne Laser Effector for Autonomous Pipeline Alignment

2014 ◽  
Vol 496-500 ◽  
pp. 1327-1332
Author(s):  
Hai Fang Liu ◽  
Rui Wang ◽  
Shi Sheng Zhong
Keyword(s):  
Natural Gas ◽  
Control Algorithm ◽  
Gas Pipeline ◽  
Remote Detection ◽  
Long Distance ◽  
Natural Gas Pipeline ◽  
Modular Software ◽  
Airborne Laser ◽  
Design Requirements ◽  
And Control

Abstract. High-accuracy beam pointing is one of the key problems in the airborne laser remote sensing of natural gas pipeline leak. In response to the domestic demand for the long-distance natural pipeline leak detection, this study proposes an airborne laser effector for autonomous pipeline alignment based on CH4/H2S detector. Mainly structured on 2DOF serial mechanism, the device under discussion is designed with a control system operated on IPC and PMAC, followed by the design of hierarchical modular software. Once completed, the device is placed for indoors pointing experiments as well as simulated airborne test. The results show the effector can conduct full-angle scan of the pod area, achieve a static measuring precision of less than 0.4m as an alignment point is about 100 meters from the laser and detect leakage in dynamic simulated experiment, which meets with the design requirements. In other words, both the design and control algorithm are proved to be feasible. The effector holds an important engineering value for solving the problem of remote detection of the natural gas pipeline leakage.

Optimization of Long Distance Natural Gas Pipeline Design Proposals Based on Multi-Objective AHM Method

2013 ◽  
Vol 756-759 ◽  
pp. 4309-4313
Author(s):  
Feng Juan Dong ◽  
Xue Fei Lu
Keyword(s):  
Natural Gas ◽  
Pressure Ratio ◽  
Gas Pipeline ◽  
New Method ◽  
Long Distance ◽  
Natural Gas Pipeline ◽  
Delivery Pressure ◽  
Design Case ◽  
Pipeline Design ◽  
Assessment Result

the new method-AHM, and nine parameters which included diameter, delivery pressure, pressure ratio of the first station, pressure ratios of intermediate stations, number of stations, investment costs of pipeline ,investment costs of stations, investment costs of operation ,equivalent cost, have been selected to evaluate design projects of the long distance natural gas pipeline. The results indicate that attribute AHM matches other methods well. The calculation result of the example indicates that AHM method can get a good assessment result for the multifactor and multi-hierarchy complicated problems. The study provides a new method and technique for designers to select the technical feasible and economic reasonable design case, which has some theoretical and practical value.

Data Analysis and Model Validation of Natural Gas Transmission Pipeline With Compressor Station

2019 ◽  
Vol 4 (3) ◽  
Author(s):  
David Cheng
Keyword(s):  
Performance Analysis ◽  
Natural Gas ◽  
Model Validation ◽  
Measurement Data ◽  
Gas Pipeline ◽  
Pipeline System ◽  
Actual System ◽  
Natural Gas Transmission ◽  
Transmission Pipeline ◽  
Performance Analysis Tools

Abstract Data from the distributed control system (DCS) or supervisory control and data acquisition (SCADA) system provide useful information critical to the evaluation of the performance and transportation efficiency of a gas pipeline system with compressor stations. The pipeline performance data provide correction factors for compressors as part of the operation optimization of natural gas transmission pipelines. This paper presents methods, procedures, and an example of model validation-based performance analysis of a gas pipeline based on actual system operational data. An analysis approach based on statistical methods is demonstrated with actual DCS gas pipeline measurement data. These methods offer practical ways to validate the pipeline hydraulics model using the DCS data. The validated models are then used as performance analysis tools in assessing the pipeline hydraulics parameters that influence the pressure drop in the pipeline such as corrosion (inside diameter change), roughness changes, or basic sediment and water deposition.

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