Huge interconnected power grids are formed in AC and DC powersystems in China. The nanoseconds, microseconds, milliseconds electromagnetic transient due to AC and DC system operation and fault, the DC converter valve...
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Huge interconnected power grids are formed in AC and DC powersystems in China. The nanoseconds, microseconds, milliseconds electromagnetic transient due to AC and DC system operation and fault, the DC converter valve movement, the load generated by changes interact in the AC and DC interconnected system, impairing AC and DC powersystems, especially leading to the commutation of DC system failures and atresia such serious incidents. Consequently, a theoretical analysis was combined with a test method to establish an over ground network, considering DC electrical networks, controlsystems and underground grounding system of the full-wave process of the UHV system, Finally, converter transformer was modeled with UMEC model, and transmission line was modeled with J-Marti frequency dependent model;moreover, valve was modeled with transistor, RLC circuit, and other units including DC controller, and DC filter and AC filter were modeled with RLC circuit. The broadband characteristics of electromagnetic transient models of key units in DC sides for the analysis of AC and DC interconnected system were also analyzed.
For some domestic large thermal power plants delivering electric energy over long distances, the sub-synchronous resonance (SSR), which is induced by the fixed series compensation (FSC), attracts much attention. Eigen...
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For some domestic large thermal power plants delivering electric energy over long distances, the sub-synchronous resonance (SSR), which is induced by the fixed series compensation (FSC), attracts much attention. Eigenvalue analysis is one of the primary methods to assess the risk and explore the countermeasure. However, for handling multi-machine and multi-mode SSR problems, no practical toolkit based on eigenvalue analysis is on hand for the moment. In this paper, a systematic modeling approach and analysis flows for the purpose of eigenvalue analysis of multimachine plant-to-grid transmission systems with FSC were proposed. The equating technique of machines and networks was presented, and the effect of the q-axis damping windings on the SSR was also explored. The applicability of the proposed method was verified with an actual multimachine system. Furthermore, its advantage over existing SMIB based eigenvalue analysis was clarified by a comparative study between the original multi-machine system and the simplified single-machine system.
China AC-DC powersystems are interconnected to form a huge power grid. The nanoseconds, microseconds, milliseconds electromagnetic transient were generated due to AC-DC system operation and fault, the DC converter va...
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China AC-DC powersystems are interconnected to form a huge power grid. The nanoseconds, microseconds, milliseconds electromagnetic transient were generated due to AC-DC system operation and fault, the DC converter valve movement, the load generated by changes in the interaction of AC-DC interconnected system electromagnetic transient, which can pose a hazard on AC and DC powersystems, in particular, can lead to the commutation of DC system failures and atresia such serious incidents. Based on the broadband characteristics model which can accurately reflect the existing AC-DC interconnected system electromagnetic transient characteristics of the key components, we applied the PSCAD/EMTDC platform to establish a computational model, and revealed DC side electromagnetic transient interaction on AC side. The results show that the DC system has little effect on AC system electromagnetic transient, In various types of failures, the overvoltage produced at side of 750 kV, 330 kV lines and bus are in the allowable range.
With the rapid development of active distribution network and demand-side response, the effective utilization of large-scale flexible load is one of the main trends of the future distribution network development. In t...
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With the rapid development of active distribution network and demand-side response, the effective utilization of large-scale flexible load is one of the main trends of the future distribution network development. In this paper, Energy Internet demonstration park has become the focus of international academy and industry. In this paper, shortcomings of the existing methods and new methods in load forecasting, power, and energy balance and planning evaluation are proposed, which emphasize mostly on the impact of flexible load on the distribution network. Then, the planning optimization method considering flexible load is discussed, and the relevant theoretical results are summarized from the aspect of uncertainty, multi-objective and multi-agent. Finally, the relevant technologies of future distribution network planning are prospected.
The cumulative installed capacity of wind power worldwide has grown rapidly in recent years. Fixed reactive powercontrol is adopted by wind turbines (WTs) to receive cycle instruction of wind farm (WF) automatic volt...
ISBN:
(数字)9781839531248
ISBN:
(纸本)9781839531255
The cumulative installed capacity of wind power worldwide has grown rapidly in recent years. Fixed reactive powercontrol is adopted by wind turbines (WTs) to receive cycle instruction of wind farm (WF) automatic voltage control system (AVCS). It does not have active voltage regulation (AVR) capability, which reduces the reliability of power system operation. Firstly, two ways of WTs AVR which QV droop control and Vac control mode are introduced in this paper. On the basis, the problems of reactive power circulation and control points inconsistency during multi-WTs voltage regulation are discussed. The problems are solved by coordination of WTs of WF AVR strategy. WF voltage transient support capability is promoted by the strategy. Effectiveness is verified by simulation case of the proposed method.
This study investigated the air-gap magnetic field distribution and inductance characteristics of a long primary sectional powered variable pole pitch linear induction motor (VPPLIM). A one-dimensional analytical mode...
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In order to better accommodate renewable energy sources (RESs), a general coordinated mechanism for modern power system has been proposed, which is simultaneously appropriate for economic dispatch and market clearing ...
In order to better accommodate renewable energy sources (RESs), a general coordinated mechanism for modern power system has been proposed, which is simultaneously appropriate for economic dispatch and market clearing under the current structure of wholesale markets. In which, the system operator can achieve a global optimum under uncertainties by investing independent aggregators (IAs) with better autonomies on trade-offs between expected profits and risks. Meanwhile, IAs with RESs are free to model their internal uncertainty in a heterogeneous manner and integrate the local information into tailored bids without revealing privacy. Moreover, a parametric-programming-based distributed (PPD) algorithm is designed to support the once-daily communication mechanism. The case studies validated the performance of the proposed mechanism.
A method for the power system transient stability assessment based on 2D combined attribute decision tree was proposed. Different from single attribute decision trees, the 2D trees combine two attributes as one automa...
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power-to-gas (P2G) can be employed to balance renewable generation because of its feasibility to operate at fluctuating loading power. The fluctuating operation of low-temperature P2G loads can be achieved by controll...
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