Damping Characteristics Analysis Based on Complex Torque Coefficient Method in Sub-Synchronous Oscillations

2014 ◽  
Vol 971-973 ◽  
pp. 988-991
Author(s):  
Han Chen ◽  
Chun Lin Guo
Keyword(s):  
Large Scale ◽  
Power Transmission ◽  
Test Method ◽  
Long Distance ◽  
Damping Characteristics ◽  
Torque Coefficient ◽  
Synchronous Oscillations ◽  
Electrical Damping ◽  
The Time Domain ◽  
Coefficient Method

Because of China's energy and load imbalance, large-scale long-distance power transmission becomes inevitable. Under this background , series compensation capacitor in the power system and HVDC developed rapidly, and the SSO (Sub-synchronous oscillations) caused by HVDC is becoming increasingly apparent. Fundamental reason of SSO lies in the sub-synchronous system negative damping characteristics, so it is necessary to analyze the system damping characteristics. The net system damping includes mechanical and electrical damping. Based on small-signal test method-complex torque coefficient method in the time-domain simulation , paper analyzed the system electrical damping and mechanical damping characteristics.

Sub-Synchronous Oscillation Caused by HVDC and the Damping Characteristic Analysis

2014 ◽  
Vol 971-973 ◽  
pp. 1353-1356
Author(s):  
Han Chen ◽  
Chun Lin Guo ◽  
Qin Lei Chen
Keyword(s):  
Large Scale ◽  
Power Transmission ◽  
Test Method ◽  
Characteristic Analysis ◽  
Long Distance ◽  
Damping Characteristics ◽  
Torque Coefficient ◽  
Electrical Damping ◽  
The Time Domain ◽  
The Impact

Because of China's energy and load imbalance, respectively, large-scale long-distance power transmission becomes inevitable. Under this background , HVDC develops rapidly, SSO (Sub-synchronous oscillations) caused by HVDC is becoming increasingly apparent. The sub-synchronous electrical damping within the frequency range is difficult to calculate. Based on small-signal test method-complex torque coefficient method in the time-domain simulation , the paper calculated the sub-synchronous electrical damping characteristics of the system and analyzed the impact of the unit interaction, DC power and the generator output on sub-synchronous electrical damping characteristics.

Damping Analysis of Subsynchronous Oscillation Caused by HVDC

2013 ◽  
Vol 732-733 ◽  
pp. 1065-1068
Author(s):  
Shi Wu Xiao ◽  
Lan Lan Shu
Keyword(s):  
Time Domain ◽  
Test Signal ◽  
Subsynchronous Oscillation ◽  
High Voltage Direct Current ◽  
Damping Characteristics ◽  
Torque Coefficient ◽  
Machine Systems ◽  
Electrical Damping ◽  
The Time Domain ◽  
Signal Method

High Voltage Direct Current transmission (HVDC) will cause torsional interaction under certain conditions. Among a variety of factors, improper rectifier control has fateful effect. In the paper, the test signal method which is the time-domain form of the complex torque coefficient approach (CTC approach) is studied. Its application conditions in multi-machine systems are summarized. Using the test signal method, impacts of DC power, DC voltage, rectifier controller parameters and generator output on electrical damping characteristics in the Suizhong system are studied based on time-domain simulation model.

The Comparative Analysis of SVC and STATCOM on Subsynchronous Oscillation Mitigation

2013 ◽  
Vol 756-759 ◽  
pp. 245-249 ◽  
Author(s):  
Jian Zhang ◽  
Xiang Ning Xiao ◽  
Ben Feng Gao ◽  
Chao Luo
Keyword(s):  
Short Circuit ◽  
Time Domain Simulation ◽  
Subsynchronous Oscillation ◽  
Damping Coefficients ◽  
Torque Coefficient ◽  
Electrical Damping ◽  
The Time Domain ◽  
Generator Terminal ◽  
Short Circuit Fault ◽  
Signal Method

The methods for subsynchronous oscillation mitigation based on SVC and STATCOM are analyzed in this paper. According to the IEEE first benchmark model, the electrical damping coefficients respectively provided by SVC and STATCOM connected at the generator terminal, as well as positive damping condition, are deduced by complex torque coefficient approach. Correlative factors which influence the two positive dampings are compared. The analysis results indicate that the positive damping provided by SVC is proportional to the size of system voltage. The positive damping provided by STATCOM is not affected by the size of system voltage, which is mostly proportional to the subsynchronous voltage produced itself. The controllers of SVC and STATCOM are designed and the positive dampings separately offered by SVC and STATCOM are optimized by phase compensation with test signal method. The time domain simulation reveals that STATCOM has stronger damping ability than SVC in the case of short circuit fault.

Analysis on Sub-Synchronous Damping Characteristic of VSC-HVDC

2013 ◽  
Vol 860-863 ◽  
pp. 2062-2067
Author(s):  
Ben Feng Gao ◽  
Jin Liu ◽  
Shu Qiang Zhao ◽  
Kun Xu
Keyword(s):  
Reactive Power ◽  
Power Level ◽  
Control Mode ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Interaction Factor ◽  
Torque Coefficient ◽  
Electrical Damping ◽  
The Impact ◽  
Coefficient Method

The study on the HVDC based on voltage-source converter focuses mainly on the control strategy while less on the impact of electrical damping on the adjacent units by VSC-HVDC. The mechanism of VSC-HVDC on inhibiting sub-synchronous oscillation is analyzed theoretically in the respect of its operation principle. Then the complex torque coefficient method realized by time domain simulation-the test signal method, is adopted to investigate the impact of the unit interaction factor, control mode, active power level and reactive power level on the electrical damping on the adjacent units.

Fatigue Damage Evaluation of Turbine Generator Due to Multi-Mode Subsynchronous Oscillation

2010 ◽  
Author(s):  
Chao Liu ◽  
Dongxiang Jiang
Keyword(s):  
Fatigue Damage ◽  
Torsional Vibration ◽  
Large Scale ◽  
Power Transmission ◽  
Significant Feature ◽  
Long Distance ◽  
Turbine Generator ◽  
Subsynchronous Oscillation ◽  
Large Scale Networks ◽  
Multi Mode

In recent years, Subsynchronous Resonance (SSR) and Subsynchronous Oscillation (SSO) are increasingly attracting more and more researchers’ interests in China. The network is encountering great changes and large-scale networks are increasingly implemented for long distance power transmission as well as various kinds of power electronic devices. Several SSO phenomena were monitored in a fossil-fired power plant in China in 2008. They were determined as complex factors’ co-activation between the network and the turbine generator. Multi-mode torsional vibration is one significant feature of torsional vibration caused by SSO. The paper simulates the multi-mode SSO based on the practical situation in China. The torsional vibration is studied to analyze the torsional vibration features under multimode SSO and the differences caused by different peak values and phases of electromagnetic torques. Based on some type of 600MW steam turbine generator, the fatigue damage of the shafts is studied.

Development of On-line Integrated Stability Control System (ISC) for Long-distance Bulk Power Transmission

2013 ◽  
Vol 133 (4) ◽  
pp. 313-323 ◽  
Author(s):  
Kuniaki Anzai ◽  
Kimihiko Shimomura ◽  
Soshi Yoshiyama ◽  
Hiroyuki Taguchi ◽  
Masaru Takeishi ◽  
...  
Keyword(s):  
Control System ◽  
Power Transmission ◽  
Stability Control ◽  
Long Distance ◽  
Stability Control System ◽  
On Line ◽  
Bulk Power

Going the Distance

2020 ◽  
Author(s):  
Ron Harris
Keyword(s):  
Large Scale ◽  
Western Europe ◽  
Family Firms ◽  
Global Trade ◽  
Long Distance ◽  
Business Corporation ◽  
Modern Economy ◽  
Key Factor ◽  
Silk Route ◽  
Passive Investors

Before the seventeenth century, trade across Eurasia was mostly conducted in short segments along the Silk Route and Indian Ocean. Business was organized in family firms, merchant networks, and state-owned enterprises, and dominated by Chinese, Indian, and Arabic traders. However, around 1600 the first two joint-stock corporations, the English and Dutch East India Companies, were established. This book tells the story of overland and maritime trade without Europeans, of European Cape Route trade without corporations, and of how new, large-scale, and impersonal organizations arose in Europe to control long-distance trade for more than three centuries. It shows that by 1700, the scene and methods for global trade had dramatically changed: Dutch and English merchants shepherded goods directly from China and India to northwestern Europe. To understand this transformation, the book compares the organizational forms used in four major regions: China, India, the Middle East, and Western Europe. The English and Dutch were the last to leap into Eurasian trade, and they innovated in order to compete. They raised capital from passive investors through impersonal stock markets and their joint-stock corporations deployed more capital, ships, and agents to deliver goods from their origins to consumers. The book explores the history behind a cornerstone of the modern economy, and how this organizational revolution contributed to the formation of global trade and the creation of the business corporation as a key factor in Europe's economic rise.

scholarly journals Future Power Train Solutions for Long-Haul Trucks

2021 ◽  
Vol 13 (4) ◽  
pp. 2225
Author(s):  
Ralf Peters ◽  
Janos Lucian Breuer ◽  
Maximilian Decker ◽  
Thomas Grube ◽  
Martin Robinius ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Co2 Emissions ◽  
Value Chain ◽  
Large Scale ◽  
New Technology ◽  
Co2 Reduction ◽  
Road Transport ◽  
Transport Sector ◽  
Long Distance ◽  
Production Of Hydrogen

Achieving the CO2 reduction targets for 2050 requires extensive measures being undertaken in all sectors. In contrast to energy generation, the transport sector has not yet been able to achieve a substantive reduction in CO2 emissions. Measures for the ever more pressing reduction in CO2 emissions from transportation include the increased use of electric vehicles powered by batteries or fuel cells. The use of fuel cells requires the production of hydrogen and the establishment of a corresponding hydrogen production system and associated infrastructure. Synthetic fuels made using carbon dioxide and sustainably-produced hydrogen can be used in the existing infrastructure and will reach the extant vehicle fleet in the medium term. All three options require a major expansion of the generation capacities for renewable electricity. Moreover, various options for road freight transport with light duty vehicles (LDVs) and heavy duty vehicles (HDVs) are analyzed and compared. In addition to efficiency throughout the entire value chain, well-to-wheel efficiency and also other aspects play an important role in this comparison. These include: (a) the possibility of large-scale energy storage in the sense of so-called ‘sector coupling’, which is offered only by hydrogen and synthetic energy sources; (b) the use of the existing fueling station infrastructure and the applicability of the new technology on the existing fleet; (c) fulfilling the power and range requirements of the long-distance road transport.

scholarly journals Network isolators inhibit failure spreading in complex networks

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Franz Kaiser ◽  
Vito Latora ◽  
Dirk Witthaut
Keyword(s):  
Complex Networks ◽  
Large Scale ◽  
Power Transmission ◽  
Power Grids ◽  
Cascading Failure ◽  
Critical Infrastructures ◽  
Daily Lives ◽  
Supply Networks ◽  
Water Transmission ◽  
Complete Collapse

AbstractIn our daily lives, we rely on the proper functioning of supply networks, from power grids to water transmission systems. A single failure in these critical infrastructures can lead to a complete collapse through a cascading failure mechanism. Counteracting strategies are thus heavily sought after. In this article, we introduce a general framework to analyse the spreading of failures in complex networks and demostrate that not only decreasing but also increasing the connectivity of the network can be an effective method to contain damages. We rigorously prove the existence of certain subgraphs, called network isolators, that can completely inhibit any failure spreading, and we show how to create such isolators in synthetic and real-world networks. The addition of selected links can thus prevent large scale outages as demonstrated for power transmission grids.

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