Provide costeffective solutions to reduce lightning overvoltage in power systems. Power consulting overvoltage protection and insulation. Overvoltage on unfaulted phase during typical range of magnitude and duration of power system temporary overvoltages. Digsilent pacific powerfactory users conference 2011 4 network component models. This allows to correlate the electrical stress caused by lightning and the electrical strength of the insulations, both having probabilistic nature. In a few more words, insulation coordination is a series of steps used to select the dielectric strength of equipment in relation to the operating voltages and transient overvoltages which can appear on the system for which the equipment is intended. Over voltages are phenomena which occur in power system networks either externally or. The task of coordinating the insulation withstand levels with the desired performance levels of. Insulation coordination free download as powerpoint presentation. Uhv ac system overvoltage and insulation coordination. Insulation coordination has become a well developed engineering practice. If the overvoltage inside the cable exceeds the lightning impulse withstand level. Assessment of overvoltage and insulation coordination in.
Crossreferences the british standards which implement international or european publications referred to in this document may be found in the bsi catalogue. The international standard iec600712 insulation coordination third edition 1996 states the following. Lightning insulation coordination is based on statistical approaches. Iec standard 60071 classifies these over voltages as. Insulation coordination aims at minimizing prob ability of an insulation failures by developing overvoltage protection concepts taking into account the specific system configuration, but also economical aspects. Calculation of the strength the study calculation of dielectric withstand characteristics of the insulation when submitted to. In its simplest form, insulation coordination is the selection of insulation strength. Power system overvoltage, surge arrester, insulation coordination. Assessment of overvoltage and insulation coordination in mixed hvdc transmission lines exposed to lightning strikes article pdf available in energies 1221. Then the insulation coordination for overhead lines was conducted according to the overvoltage level. Overvoltages 1 2 3 4 5 6 106 104 102 100 102 104 t s u p.
Insulation coordination encompasses all aspects of the power system and attempts to ensure uninterrupted supply of power under the worst overvoltage and environmental conditions. Ground potential rise at the pv plant must be considered be. New method of protection against lightning overvoltages for high. Pdf assessment of overvoltage and insulation coordination in. Coordination is an integral part of the design process, giving criteria that are satisfied through insulation design and through overvoltage control and protection.
In this work, we have analyzed the factors that affect the level of overvoltage inside the cable by simulating a fast front model in pscad. Sudden changes in electrical network structure give rise to transient phenomena frequently resulting in the creation of an overvoltage or of a high frequency wave. It has been found that the insulation coordination measures do not alter the. Lightning protection and transient overvoltage calgary. All simulations have been conducted using matlab and atpemtp software.
Zinc oxide overvoltage control and insulation coordination. Overvoltages and insulation coordination training course industry need this course provides engineers with a fundamental understanding of transient phenomena common to electric power systems. As such, a uhvdc transmission system has more operation modes than conventional dc transmission projects see chapter 3. Part 2, characteristics as machinery steadystate, transient, dynamic stability induction generator and motor induction machine. Insulation coordination of overhead transmission lines. Jul 25, 2018 insulation coordination in power system was introduced to arrange the electrical insulation levels of different components in the electrical power system including transmission network, in such a manner, that the failure of insulator, if occurs, confindes to the place where it would result in the least danmage of the system. The material is especially suited for those who simulate transients with tools such as emtp, those who analyze waveforms from. Understand the key principles and concepts regarding lightning protection and transient overvoltage. Insulation coordination, different types of electrical stress working voltage, lightning and switching over voltages and the behavior of different insulation systems in action of these stresses, represent the central part of this course. Overvoltages and insulation coordination coursewebs. Also resulting from this analysis, a methodology for compacting. Insulation coordination in power system electrical4u.
Abstractinsulation coordination methodologies are analyzed and a program built by the author is presented, which executes the insulation coordination algorithm proposed by the standards of the international electrotechnical comission iec. This practice is where the characteristics of the system, insulation of all forms, and arresters of all forms cross paths. In order to promote public education and public safety, equal justice for all, a better informed citizenry, the rule of law, world trade and world peace, this legal document is hereby made available on a noncommercial basis, as it is the right of all humans to know and speak the laws that govern them. Interaction phenomena between parallel ac and dc overhead lines. However, as uhv system lines are characterized by a larger transmission capacity, longer transmission distances, and large reactive power the reactive power per 100 km of kv lines reaches up to about 530 mvar such that. Overvoltages and insulation coordination in mv and hv. Surge arresters play an important role in reaching this goal. In cooperation with graz university of technology university of zagreb university of sarajevo 3 days training grazaustria 1820 october 2010 use of the emtprv software for insulation coordination studies. Apply the principles of lightning protection to other industries, such as industrial, chemical, renewable energy, nuclear, and oil and gas.
This chapter provides an example of lightning insulation coordination. Although simple in concept, involving comparisons between maximum network overvoltages and minimum insulation breakdown voltages, in practice the process is complex. A supporting routine available in most transients programs allows users to. Insulation coordination ic is the correlation of the insulation of various equipments to be protected transfor. Longduration voltage variation is commonly defined as the rootmeansquare rms value deviations at power frequencies for. The method and the technologies to control the overvoltage and the impact of the size of the resistor to the overall insulation coordination were also.
Standards and insulation hv insulation coordination p. In some applications, the subject of overvoltage categories may result in a need to change from a umg 604 with 300 v catiii to a umg 508 with the overvoltage category 600 v catiii, i. Uhvdc system overvoltage and insulation coordination. An overview on overvoltage phenomena in power systems. The first step in the insulation coordination is the determination of the representative over voltages in the system urp to which the electrical circuit is subjected to, under various operating conditions and switching phenomena. Modeling breakers for studying transient recovery voltage. Mar 17, 2011 overvoltage is classified as a longduration voltage variation phenomena, which is one of the general categories of power quality problems mentioned in the second post of the power quality basics series of this site. Overvoltages and insulation coordination in mv and hv studiecd. Simulation of interaction phenomena between parallel ac and dc overhead lines. Gel28, insulation coordination, which has the responsibility to. Im directional distance relay and rx diagram lightning, switching surge phenomena and breaker switching overvoltage phenomena insulation coordination harmonics and waveform distortion power.
Efficient discharge of over voltages due to lighting strike. The lightning strikes can not only result in flashover of overhead line ohl insulators but can enter the cable and permanently damage its insulation if adequate insulation coordination measures are not taken. Generally, for existing insulation coordination studies the power system has been modeled either by. Overvoltage and insulation coordination of overhead lines in. The voltagesourced converterbased hvdc link, including the modular multilevel converter mmc configuration, is suitable for wind power, photovoltaic energy, and other kinds of new energy delivery. Overvoltages and insulation coordination etf eeo pki 4865. Lightning surges fastfront overvoltage switching surges slowfront overvoltage temporary. Electrical safety, power quality, electrical analysis and osha and nfpa 70e training conducted by qualified engineers who perform thousands of power systems, power quality and arc flash analyses each year, as well as sit on ieee and other industry boards to help develop safety standards. Power system dynamics with computerbased modeling and. Insulation coordination and voltage transients for industrial. In addition, the steadystate operating voltage on electrical equipment at converter stations varies with the engineering design and operation mode. The method and the technologies to control the overvoltage and the impact of the size of the resistor to the overall insulation coordination were also excluded from this study.
Pdf an overview on overvoltage phenomena in power systems. Introduction lightning insulation coordination insulation coordination is required to ensure equipments insulation shall withstand voltage stress caused by lightning strike. Electrical safety power quality analysis risk mitigation. Insulation coordination for converter station of 800kv uhvdc project from jinping to sunan j. Our experience and understanding shows that many users are not sufficiently familiar with this subject.
This deals with lightning and switching overvoltages ovs in a power system and rarely with power frequency 50 or 60 hz faults. Introduction lightning overvoltages on hv transmission lines. Calculation of lightning overvoltage failure rates for a gas. Study on overvoltage and insulation coordination of dc filter. Thus, this work seeks to model a lightning induced over voltage transient. When any over voltage appears in the electrical power system, then there may be a chance of failure of its insulation system. In terms of overvoltage and insulation coordination, a uhv system is similar to an extrahighvoltage ehv system. A list of organizations represented on this committee can be obtained on request to its secretary.
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