High Voltage Direct Current Projects

High Voltage Direct Current projects list

HIGH-VOLTAGE direct current (HVDC) systems have become a viable option for accommodating bulk power transmission over long distance. They can serve as technically feasible solutions for connecting large offshore wind firms located farther than 70 km away from the coast. Furthermore, due to their innate ability to connect asynchronous systems, HVDC technology can also be suitable means for interconnection between different AC systems to improve the security of power supply. A large number of point-to-point HVDC link projects have been launched and already started their commercial operation.

HVDC allows power transmission between unsynchronized AC transmission systems. Since the power flow through an HVDC link can be controlled independently of the phase angle between source and load, it can stabilize a network against disturbances due to rapid changes in power. HVDC also allows transfer of power between grid systems running at different frequencies, such as 50 Hz and 60 Hz. This improves the stability and economy of each grid, by allowing exchange of power between incompatible networks.

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High Voltage Direct Current Projects

High Voltage Direct Current

A Two-Level, 48-Pulse Voltage Source Converter for HVDC Systems

ABSTRACT

This paper deals with an analysis, modeling and control of a two level 48-pulse voltage source converter for High Voltage DC (HVDC) system. A set of two-level 6-pulse voltage source converters (VSCs) is used to form a 48-pulse converter operated at fundamental frequency switching (FFS). The performance of the VSC system is improved in terms of reduced harmonics level at FFS and THD (Total Harmonic Distribution) of voltage and current is achieved within the IEEE 519 standard. The performance of the VSC is studied in terms of required reactive power compensation, improved power factor and reduced harmonics distortion. Simulation results are presented for the designed two level multipulse converter to demonstrate its capability. The control algorithm is disused in detail for operating the converter at fundamental frequency switching.

 KEYWORDS

Two-Level Voltage Source Converter

HVDC Systems

Multipulse

Fundamental Frequency Switching

Harmonics.

 SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

1

Fig. 1 A 48-Pulse voltage source converter based HVDC system configuration

 EXPECTED SIMULATION RESULTS:

2

Fig. 2 Steady state performance of proposed 48-pulse voltage source converter

3 4

Fig. 3 Dynamic performance of proposed 48-pulse voltage source converter

 5 6

 Fig. 4 Waveforms and harmonic spectra of 48-pulse converter (a) supply voltage (b) supply current (c) converter voltage

 CONCLUSION

A 48-pulse two-level voltage source converter has been designed, modeled and controlled for back-to-back HVDC system. The transformer connections with appropriate phase shift have been used to realize a 48-pulse converter along with a control scheme using a set of two level six pulse converters. The operation of the designed converter configuration has been simulated and tested in steady sate and transient conditions which have demonstrated the quite satisfactory converter operation. The characteristic harmonics of the system has also improved by the proposed converter configuration.

 REFERENCES

[1] J. Arrillaga, Y. H. Liu and N. R. Waston, “Flexible Power Transmission, The HVDC Options,” John Wiley & Sons, Ltd, Chichester, UK, 2007.

[2] Gunnar Asplund Kjell Eriksson and kjell Svensson, “DC Transmission based on Voltage Source Converter,” in Proc. of CIGRE SC14 Colloquium in South Africa 1997, pp.1-8.

[3] Y. H. Liu R. H. Zhang, J. Arrillaga and N. R. Watson, “An Overview of Self-Commutating Converters and their Application in Transmission and Distribution,” in Conf. IEEE/PES Trans. and Distr.Conf. & Exhibition, Asia and Pacific Dalian, China 2005.

[4] B. R. Anderson, L. Xu, P. Horton and P. Cartwright, “Topology for VSC Transmission,” IEE Power Engineering Journal, vol.16, no.3, pp142- 150, June 2002.

[5] G. D. Breuer and R. L. Hauth, “HVDC’s Increasing Poppularity”, IEEE Potentials, pp.18-21, May 1988.

A New Control Strategy for Active and Reactive Power Control of Three-Level VSC Based HVDC System

ABSTRACT

This paper displays another control procedure no doubt and receptive power control of three-level multipulse voltage source converter based High Voltage DC (HVDC) transmission framework working at Fundamental Frequency Switching (FFS). A three-level voltage source converter replaces the regular two-level VSC and it is intended for the genuine and responsive power control is each of the four quadrants task. Another control strategy is produced for accomplishing the receptive power control by changing the beat width and by keeping the dc connect voltage consistent. The enduring state and dynamic exhibitions of HVDC framework interconnecting two unique frequencies arrange are shown for dynamic and responsive forces control. Complete quantities of transformers utilized in the framework are decreased in contrast with two dimension VSCs. The execution of the HVDC framework is likewise enhanced as far as decreased music level even at essential recurrence exchanging.

 

BLOCK DIAGRAM: 1

Fig. 1 A three-level 24-Pulse voltage source converter based HVDC system

 CONTROL SCHEME

2

Fig. 2 Control scheme of three-level VSC based HVDC system using dynamic dead angle (β) Control

EXPECTED SIMULATION RESULTS

3

Fig. 3 Performance of rectifier station during simultaneous real and reactive power control of three-level 24-pulse VSC based HVDC system

4

Fig. 4 Performance of inverter station during simultaneous real and reactive power control of three-level 24-pulse VSC based HVDC system

5

Fig. 5 Variation of angles (δ) and (β) values of three-level 24-pulse VSC based HVDC system during simultaneous real and reactive power control

CONCLUSION

Another control technique for three-level 24-beat voltage source converter setup has been intended for HVDC framework. The execution of this 24-beat VSC based HVDC framework utilizing the control technique has been exhibited in dynamic power control in bidirectional, free control of the receptive power and power quality enhancement. Another powerful dead point (β) control has been presented for three-level voltage source converter working at crucial recurrence exchanging. In this control the HVDC framework activity is effectively exhibited and furthermore an examination of (β) esteem for different responsive power necessity and symphonious execution has been completed in detail. In this way, the determination of converter task locale is progressively adaptable as indicated by the necessity of the responsive power and power quality.