Minimization of Transmission Loss in Application of HVDC Networks under Load Increase Scenario (original) (raw)
Related papers
Enhancing Power Transmission Stability with HVDC Systems During Load Contingencies
Journal Européen des Systèmes Automatisés, 2024
The transmission network of a power system is important in connecting interactions between the generation and distribution sides. A significant aspect in the power system profile is voltage improvement. This study intends to examine the impact of inserting High Voltage Direct Current (HVDC) on the system's voltage stability, network power losses and power transfer capacity of transmission network under several cases of load contingency. IEEE 57-Bus test system is used for testing the addition of HVDC transmission based on genetic algorithm. Modeling of point-to-point HVDC transmission and multi-terminal HVDC transmission is carried out using the Power System Simulator for Engineering (PSS/E) version 32 Package Program (A collection of computer programs and organized data files called PSS/E software was developed by Siemens PTI to handle the fundamental tasks of power system performance simulation work). The system's performance was compared with and without the HVDC inserted under different loading scenarios: 5%, 10%, and 20% of the total load. The comparative results can show that active power losses at the normal load case are reduced by 55.714% after inserting point to point HVDC topology, and after inserting multi-terminal HVDC topology reduced by 68.214%. Also, the reactive power losses reduce by 55.714% after inserting point to point HVDC topology and after inserting multi-terminal HVDC topology reduced by 66.830% at the same case. The results shown that inserting HVDC Transmission to the system gives better improvement in bus voltage profile and a significant reduction in total network power losses and increase in power transfer capacity of transmission network. The results also showed that multi-terminal HVDC transmission is better in voltage improvement and total power losses reduction when HVDC Transmission is added to the system.
Stability improvement of a HVDC transmission link between weak AC systems by multi-terminal scheme
2013 Africon, 2013
High Voltage Direct Current (HVDC) schemes are becoming a more attractive solution as they have been used extensively in interconnected weak power AC systems. But, the problem of voltage stability for weak AC systems interconnected by a DC link is critical especially during islanding conditions. The approach to improve more on the stability of such system would be to device a means of injecting locally controlled dc power on the dc-link transmission corridor forming a radial multi-terminal HVDC. However, continuous injection of DC power on the dc line of the VSC HVDC link though will increase the power transfer capability of the system but should have a limit otherwise it will lead to instability of the system. In this paper, a detailed VSC HVDC model and a simple analytical technique using the principle of uniform loading to determine penetration limit is presented. The techniques is applied to our case study and validated with a simulation result. Critical contingencies such as sudden island conditions, threephase to ground fault are simulated with and without DC power penetration. Results show the stability support on the AC side networks by DC power injection on the dc-link.
Aspects on infeed of multiple HVDC into one ac network
2005
The paper covers the fundamental aspects of integration of multiple HVDC links feeding power into different points in the same ac network area. Considering that the number of power systems that includes this type of application of HVDC is increasing, the performance needs to be studied in detail. There are a number of technical aspects related to multiple infeed configurations with HVDC transmission links. Focus on critical network conditions where the strength of the system is relatively low as compared to the amount of power that the HVDC transmission links are feeding into the system will be given in this paper. In those cases the phenomena of concern that might occur which could result in adverse interaction among the HVDC transmission links and the receiving ac network are discussed. The following basic issues are addressed in the paper: voltage and power stability; coordination of power or voltage modulation between different HVDC links for stabilization of the ac network; nee...
Investigating theWorking Procedure of HVDC Electric Power Transmission Systems
High-voltage, direct current (HVDC) electric power transmission system are the well known and commonly used systems in modern and large scale power systems. In these systems, the electricity is transmitted through high voltage DC lines for the sake of reducing costs and losses. In this paper, the working procedure, advantages and disadvantages of these systems is thoroughly reviewed and discussed.
Energies, 2021
High-voltage direct current (HVDC) has received considerable attention due to several advantageous features such as minimum transmission losses, enhanced stability, and control operation. An appropriate model of HVDC is necessary to assess the operating conditions as well as to analyze the transient and steady-state stabilities integrated with the AC networks. Nevertheless, the construction of an HVDC model is challenging due to the high computational cost, which needs huge ranges of modeling experience. Therefore, advanced dynamic modeling of HVDC is necessary to improve stability with minimum power loss. This paper presents a comprehensive review of the various dynamic modeling of the HVDC transmission system. In line with this matter, an in-depth investigation of various HVDC mathematical models is carried out including average-value modeling (AVM), voltage source converter (VSC), and line-commutated converter (LCC). Moreover, numerous stability assessment models of HVDC are outl...
Transient stability analysis of VSC HVDC transmission with power injection on the DC-link
TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES, 2015
The utilization of a DC-link transmission corridor of embedded VSC HVDC for a DC power injection from renewable energy sources to increase the power flow capability and AC network stability support is a promising technology. However, DC faults on the DC transmission line are likely to threaten the system's operation and stability, especially when the DC power injection exceeds certain limits. A DC single line-to-earth fault is the most likely fault scenario and its effect on the VSC HVDC operation will depend on the earth-loop impedance. Adding an injection point on the DC-link will reduce the earth-loop impedance, hence imposing a danger of increasing the earth fault current. Therefore, in this paper, a VSC HVDC with a DC power injection on the DC-link is studied, the DC-line-to-earth fault is analyzed in the time domain, and its effects on the DC and AC sides of the system are presented. The analysis is based on a developed state-space representation of the system under a single-line-to earth fault. The zero-input zero-state (ZIZS) response is used to find the solution of the state-space representation. In order to correlate the state-space solution with a simulation, the system is modeled in MATLAB/Simulink. Interestingly, it was observed that a quick recharging of the DC-link capacitor due to a power injection created an additional damping of the postfault oscillations of the AC-side power angle and the DC-side voltage and power oscillations, hence enhancing transient stability.
Long extra high voltage (EHV) ac lines cannot be loaded to their thermal limits in order to keep sufficient margin against transient instability. With the scheme proposed in this paper, it is possible to load these lines very close to their thermal limits. The conductors are allowed to carry usual ac along with dc superimposed on it. The added dc power flow does not cause any transient instability. This paper presents the feasibility of converting a double circuit ac line into composite ac-dc power transmission line to get the advantages of parallel ac-dc transmission to improve stability and damping out oscillations. Simulation and experimental studies are carried out for the coordinated control as well as independent control of ac and dc power transmissions. No alterations of conductors, insulator strings, and towers of the original line are needed. Substantial gain in the loadability of the line is obtained. Master current controller senses ac current and regulates the dc current orders for converters online such that conductor current never exceeds its thermal limit. The present paper is implemented by using MATLAB/SIMULINK. Key word: Extra high voltage (EHV) transmission, flexible ac transmission system (FACTS), simultaneous ac-dc power transmission.
Trends for future HVDC Applications
During their development, power systems become more and more interconnected and heavily loaded. With the increasing size and complexity of systems and as the result of the liberalization of the electrical markets, needs for innovative applications and technical improvements of the grids will further increase. HVDC plays an important role for these tasks. Commercial applications of HVDC started in the 1950ies. In the meantime, HVDC became a reliable and economically important alternative for AC transmission, offering advantages in the operation of power systems in addition to the power transfer. The paper discusses expected present and future HVDC applications. Integration of HVDC into AC systems will be used more frequently as it can simplify the system configuration, control load flow and, at the same time, it improves the dynamic system performance and increases the system reliability. For the interconnection of large power systems HVDC offers technical and economical advantages, especially if the interconnection is weak. The connection of remote power stations to the system, e.g. offshore wind generation, can be effectively put into practice by means of HVDC. Advantages of these applications will be discussed and demonstrated by implemented projects. KEY WORDS: Power system development, use of HVDC, types of HVDC transmissions, integration of HVDC into AC systems, project examples
Proceedings of the IEEE, 2017
The use of DC power networks, either at high voltage or at medium voltage, is being increasingly seen in modern smart grids. This is due to the flexible control possible with DC and its ability to transmit and distribute power under circumstance where AC networks are either unable to, or less economic. This paper provides an overview of the evolution of High Voltage DC transmission from early Thury systems, to modern ultra-high voltage DC and multi-terminal voltage-source converter systems. The operation of both current-source and voltage source systems is discussed, along with modelling requirements. The paper provides a snapshot of the state-of-theart of HVDC with copious references to enable in-depth reading. Key developments over the last twenty years are highlighted. Issues surrounding multi-terminal operation and DC protection are explained as are drivers in economics and policy.
2018
In this paper we introduce a HVDC transmission between two buses of an IEEE 9bus system with transient and dynamic analysis of rotor angle deviation of the three synchronous generators. The deviation of the generators is maintained in synchronization during steady state and after fault transient. Comparison of HVDC VSCs with different controllers is presented with P, PI and PID controllers. Modeling and simulation is carried out in MATLAB software with graphical representations. IndexTerms – HVDC links , Powerflow Controllers, Rotor angle deviation,VSCs