The modern high voltage direct current hvdc transmission technology depends on the development of power electronics based on the semiconductor devices. Efficient and well proven protocols in conjunction with the standby server handling. The reasons for choosing hvdc rather than hvac in a specific case are very complex. Hvdc transmission system converter can be obtained by analytical modelling. See who you know at hvdc control systems, leverage your professional network, and get hired. Fault studies needs to be performed for a variety of fault types, locations, and active and reactive setpoints, to determine the worstcase scenario current surges and voltage sags. Building a hvdc centralized control system to integrate all of the independent hvdc systems, is helpful to.
The method is performed by a control unit of an hvdc system. Design, control and application of modular multilevel converters for hvdc transmission systems is a comprehensive guide to semiconductor technologies applicable for mmc design, component sizing control, modulation, and application of the mmc technology for hvdc transmission separated into three distinct parts, the first offers an overview of mmc technology, including. High voltage direct current hvdc systems grid solutions. Engineer level 8 technical analysis foreign power purchase agreement branch power purchase agreement division electricity generating authority of thailand.
Besides, we are also aiming to promote technology based products and solutions including technical training courses for audience who are eager to learn about new developments in science and technology. Hvdc consultants unit vector solutions west yorkshire. To assist the designers of transmission systems, the components that comprise the hvdc system, and the options available in these components, are presented and discussed. Unit vector solutions primarily provides software engineering consultancy in the power electronics, hvdc and signal processing. Introducing the industrys first hvdc solution to implement a worldclass digital measurement system fully based on iec 61850. But in case of hvac system, synchronization of the supply frequency is must. In this role you will use your experience and expertise to lead and guide the controls software project team in developing and implementing solutions based on standard components.
Thanks to the modularity and high performance of the mach equipment, the type of hardware and system software used for a vschvdc control system are. High voltage direct current hvdctransmission systems. The modular multilevel converter mmc is an emerging and attractive topology for the highvoltage direct current hvdc transmission system. For high voltage direct current hvdc applications, the control and protection system plays an essential role in the overall performance of the transmission system. Fast frequency support control in the gb power system. A current limitation strategy for mmc is derived and its impact on the performance of the hvdc transmission system is verified through simulations. Comparison of ccc and lcc in hvdc system sciencedirect. Ge power launches new innovations at cigre 2018 including. The necessity of the hvdc centralized control system is analyzed, and studies confirm its feasibility. The power flow in hvdc system can easily be controlled at high speed. The control system is the brain in hvdc transmission systems. Siemens cyber security services hvdc services siemens. Also, some specific tests could be done to check the performance of the each controller i. The system which uses the direct current for the transmission of the power such type of system is called hvdc high voltage direct current system.
In contrast to linecommutated hvdc transmission, the polarity of the dc link voltage remains the same with the dc current being. The hvdc systems are mainly classified into three types. The gws is connected to the process via the lan together with the other workstations. Principles of hvdc controls control of dc voltage dc voltage is varied by means of a converter bridge in rectifier operation the power flow is from the ac system to the dc system the power flow is changed from the dc system to the ac system by reversing the dc voltage. Basic concept operation and control of hvdc transmission. Through this modular twoday hvdc training course, dnv gl responds to the need for more knowledge and understanding regarding this subject.
The dynamics of the positive, negative, and zerosequence components are. In 1995 abb announced a new concept for hvdc converter stations, hvdc with capacitor commutated converters ccc, which further improves the performance of hvdc transmissions. Today, hvdc classic systems from siemens transmit up to 10 gw of power, this way providing the secure, stable, and profitable backbone for todays increasingly complex transmission systems as well as for grid interconnection and for uhvdc transmission. Basic concept, operation and control of hvdc transmission system. Hence, lowering the investment cost for realizing the mtdc system for the dctso, and enabling the system suppliers to utilize their current hvdc link concepts, without change in the mtdc system, by utilizing the ifc software as the core part of the solution. The power control is achieved by one amongthe subsequent three alternatives 12.
One pole, one set of conductor for transmission and current return path is through earth. Using simulink and simscape electrical, he also built a plant model that included an ac grid connection, transformers, and. Hvdc is used as an alternative to ac for transmitting electrical energy over long distances or between ac power systems of different frequencies. The solution allows simulation of thermal stress on a transformer and thus helps the operator to optimize and control the transformer performance and. Us20090279328a1 hvdc system and method to control a. This paper presents a generalized mathematical model for mmc in hvdc applications under balanced and unbalanced grid conditions. Stateoftheart model based design control system that minimizes project risk and ensures optimal and accurate performance by direct deployment into the system software. High voltage dc hvdc link software hvdc transmission.
Ac1 ac2 submarine dc cable hvdc line earthwater return path. The abb ability modular advanced control for hvdc mach control system provides unequalled calculation capacity and enables a high degree of integration and handling for all control and protection functions. The use of microcomputer control equipment in todays projects has also contributed to hvdcs current success as a powerful alternative to ac power transmission. Digital twin operation system for hvdc transformer. Hvdc systems utilize power electronics technology to convert ac and dc voltage, and are ideal for supporting existing systems or building new power highways. The lead control software engineer provides technical leadership for a software project team whilst implementing their hvdc control system.
The supply frequencies may or may not be equal on the two sides. An improved droopbased control strategy for mthvdc. A modified circulating current suppression controller is proposed to eliminate the voltage ripples in the dclink. The ssdc eliminates torsional instabilities caused by interaction between conventional hvdc. Hvdc system can produce its own voltage waveform independent of the ac system, which means that a vschvdc system has the potential to be connected to very weak ac systems. Design, control, and application of modular multilevel. Hubandspoke with ac links and hvdc backtoback station as is implemented in, for example, the kriegers flak combined grid solution project. With the control strategy, the hvdc system can provide a.
The ac and hvdc substation, the interconnecting of an hvdc lines and earth electrodes are the main components of an hvdc system. Most electrical power transmission involves a 3phase hvac system. Hvdc converters capable of converting up to two gigawatts gw and with voltage ratings of. High voltage dc transmission system electronics hub. The communication to a remote scada system is performed via a serial. Microprocessor based system for the development of control. This paper represents a simple model of hvdc transmission system in which the converter and filter have been designed to increase stability of power transmission. The principal characteristic of vschvdc transmission is its ability to independently control the reactive and real power flow at each of the ac systems to which it is connected, at the point of common coupling pcc. In order to fully utilize the potential of the vschvdc system for weakacsystem connections, a novel control method, i. Hvdc systems always maintain the power flow as long as the voltage of the systems linked by hvdc is maintained at certain limits. The integrated modeling of the hvdc link is utilized to analyze steadystate and dynamic behavior of acdc transmission networks, such as optimal power flows, contingency, shortcircuit, harmonics, protection, selectivity, and transient stability studies. Vectorcurrent control inherits poor performance for weak.
Chongru liu 1 north china electric power university, beijing, china 2. The control functions for an hvdc system shall include despatch control, operational control as well as supervisory control and data acquisition scada functions. The operating range of the ideal converter theory from. For high voltage direct current hvdc applications, the control and protection system plays an essential role in the over all performance of the transmission system.
Pioneered reliable hvdc control methods, hybrid combination of hvdc with facts, utilization of facts devices for deicing and multiterminal hvdc. The control and pro tection system adopted by abb power systems uses the latest technology from the fields of electronics and microprocessors. Spencer ogden hiring hvdc lead control design engineer. Control, dynamics and operation of multiterminal vschvdc. Etap vschvdc transmission is used to simulate and analyze the transmission of ac and dc electrical power flow across the grid using unified power flow. The system which uses the direct current for the transmission of the power such type of system is called an hvdc high voltage direct current system. The gate way station gws is the interface rtu emulator between the hvdc control equipment and the owner scada system. Vschvdc transmission system modeling model and simulate high voltage direct current hvdc transmission using voltage source converter technology for power grids and offshore wind parks. This research is based on the cigre hvdc benchmark modelin pscad software,the test system is often used for hvdc control studies as the standard system, we can add similar program and emulator to the main circuit modelfor different dc control equipment and control strategies1in this paper we deeply researched the bus voltage and current level. Modeling and control of a modular multilevel converter. The control and protection system adopted by abb power systems uses the latest technology from the fields of electronics and microprocessors.
Events generated in the ps800 hvdc control computer system will immediately be sent by the sql client to the sql server. Hvdc converter technologies training course dnv gl. In this thesis, the modeling and control issues for vschvdc links connected to weak ac systems are investigated. Further easy to comprehend analytical model in universally available software like matlabsimulink can help in fast spread of complex hvdc system knowledge also to those who are responsible for operation and maintenance of these systems thus bringing large benefits. Mechanisms in the server ensures that all events are properly stored in the sql database.
Most commercial hvdc plants now operating are equipped with the same type of control system, the socalled individual phase control system. Analysis of the hvdc control interaction or resonance with the system should be performed to evaluate risk of potential instabilities. The system consists of the station control and monitoring servers, operator workstations, control and protection main computers, digital signal processor units, io systems and valve control units. Ac dc 2 north china electric power university, beijing 3. In acdc grids, two parameters should be considered. The hvdc system is less expensive and has minimum losses. Vschvdc is superior to lcchvdc for mtdc applications due to its. Modeling and control of vschvdc links connected to weak. It transmits the power between the unsynchronized ac system.
An hvdc converter converts electric power from high voltage alternating current ac to highvoltage direct current hvdc, or vice versa. A method to control a voltage source converter in a hvdc system includes controlling a frequency and a voltage amplitude of an ac voltage generated by the voltage source converter independently of the conditions in an ac network connected to the voltage source converter. Hvdc high voltage direct current siemens high voltage direct current systems hvdc provide the most efficient way of energy transmission over long distances and to support the improvement of the grid stability. Pdf analysis and control of hvdc transmission power system.