Current differential line protection current differential relaying is a method of extending the benefits of differential protection as applied to transformers, buses or generators to the protection of transmission lines. This addendum contains information that relates to the l90 line differential relay relay, version 4. In the past they were used for differential protection with analog 50 hz measured value comparison and for phase comparison protection by implementation of modulated voice frequency signal transmission. Provides line current faults and differential protection to power lines. In addition to complete line protection, woodwards system line relays offer measuring and control functions and integrated backup protection. Line differential protection and control red615 ansi feeder. Use the sel311l line current differential relay with integral fourzone distance backup for easytoapply, highspeed line protection. The highimpedance input is created by an internal impedance, typically resistive, of 2000 ohms or higher. Pdf line current differential protection automation and. High impedance busbar differential protection valence. The current differential principle is considered to be suited to protect threeterminal lines and it does not need to contend with problems associated with voltage, loading, and swings. Ansi transformer connections daby or dy1 a b 2 1 1 2 b c 2 1 c a 2 1 a b c a a. Addendum this addendum contains information that relates to the l90 line differential relay relay, version 4.
However, a threeterminal line may affect line current differential protection schemes if outfeed conditions occur during internal line. Pdf research on differential protection algorithms of. Protection systems applied to these may be broadly classified as unit and nonunit protection systems. Differential protection relay for two line ends the 7sd610 relay is a differential protection relay suitable for all types of applications and incorporating all those functions required for differential protection of lines, cables and transformers. A new approach to current differential protection for transmission lines m. The complexity of protecting threeterminal transmission lines. Modern line current differential protection solutions. This video outlines the basic principles behind differential protection and is a sample of the full 2. Line current differential protection relay electrical. Line differential protection and control red615 ansi.
Line differential protection siprotec 5 siemens global. Current differential line protection applications current differential line protection is a fundamentally different scheme than the directional comparison line protection schemes, which brings with it both advantages and disadvantages. The differential protection used for power transformers is based on merzprize circulating current principle. Differential protection protection of transformer, motor. Jun 23, 20 in differential protection scheme, the current entering at one end of the line and leaving from other end of the line is compared. The sel311l relay implements line current differential protection using communications interfaces, a processor, and contact outputs separate from those used for backup protection and control. Synchronization errors show up as phase angle offset, where identical currents produce phasors with different phase angles, and transient errors, where changes. The protection for internal fault in such type of transformer is to be provided by using differential protection system. The paper describes proposed and pscademtdc modeled test systems for testing the differential relay algorithms used for protection of power transformers. Protection functions bias differential protection 87 harmonic restraint protection over fluxing i. Abstract based on the analysis of a specific relay model and an. In differential protection scheme, the current entering at one end of the line and leaving from other end of the line is compared.
In 9 an adaptive current line differential protection scheme is proposed to improve the dependability and security of the transmission line differential function. Line current differential protection creates challenges for relay design and application. Transformers and compensation coils within the differential protection. L to limit current through relay to line charging currents flow in at one end of the feeder only and is therefore potentially capable of unbalancing a protective system. L to limit current through relay to line differential relays and at the emerging needs for new functions and features, this paper outlines general design directions for a next generation line current differential protection system. Ge multilin l90 line differential relay i table of contents 1. The introduction of digital technology has led to further improvements in bus differential. The proposed systems can be used to test new differential protection algorithms and real. Use single or dual differential channels for reliability. Differential protection schemes are mainly used for protection against phasetophase fault and phase to earth faults. Differential protection is based on kirchhoffs laws, stating that all current into a network node shall add up to 0 in an ideal system. Modern line current differential protection solutions schweitzer. The paper provides a utility perspective on needs and expectations for a new line current differential relay.
Comparing current flowing into a line to the current flowing out of the same line allows for a simple protection scheme. Wire connections have a limited transmission bandwidth 3. Abstractparalleling current transformers cts is a common practice in differential or line protection applications. Line differential protection ied red670 telecommunication. Hvac high voltage alternating current cable system, a new approach to emtdcpscad. Transformers and compensation coils within the differential protection zone are protected by. High impedance busbar differential protection minimum allowable ct saturation voltage calculation. Siprotec 4 7sd61 differential protection relay for two. Pilot wire differential relays device 87l distance protection.
Under normal working condition, the two currents at both ends are equal and pilot wires do not carry any current, keeping relays inoperative. Red615 is also designed for the protection of line differential applications with a transformer within. Fundamental overcurrent, distance and differential. The siprotec 7sd82 line differential protection has been designed particularly for the costoptimized and compact protection of lines in mediumvoltage and highvoltage systems. Protection relays differential relays b high impedance differential protection. Mohammed tawfeeq alzuhairi 321 differential protection differential protection is the best technique in protection. Directional earthfault protection, low stage, instance 1 deflpdef1 i0 1 67n1 1 directional earthfault protection, low stage, instance 2 deflpdef2 i0 2 67n1 2 directional earthfault protection, high stage protection line differential protection and related. Fundamental overcurrent, distance and differential protection. Pdf modern line current differential protection solutions. Alexander ge corporate ge power management research and development malvern, pa schenectady, ny updated and presented by subhash c.
The principle of differential busbar protection is very simple. A detailed overview of the additional featured protection modules can be found in this pdf. Line differential protection scheme modelling for underground 420. Apply subcycle current differential protection with included fourzone distance and directional overcurrent backup. Differential protection is the best technique in protection. Transmission line protection principles 9 time synchronized between the line ends for the differential calculation to be correct. Line differential protection is a strict selective object protection. You can choose from many popular fiber and multiplexed communications options. Siprotec 4 7sd61 differential protection relay for two line ends. Relay are both phasesegregated, current only relays. We calculated that the voltage across the nonsaturated ct, when another ct saturates, is 83. Differential protection tends to be extremely accurate. Hence, total current entering into a bus section is equal to total current leaving the bus section. Line differential protection substation automation.
Line differential protection and control red615 application. View and download abb red670 commissioning manual online. When applied to transmission lines, current differential protection requires a communications channel to receive currents from the remote terminals. Siprotec 4 7sd5 line differential protection with distance. Line differential protection woodward offers line differential protection with fiber optic communication, because it is the best way to protect an overheadline or cable. Red615 is a phasesegregated twoend line differential protection and control relay designed for utility and industrial power systems, including radial, looped and meshed distribution networks with or without distributed power generation. Red615 is a phasesegregated, twoend, line differential protection and control relay for protection, control, measurement and supervision of overhead line and cable feeders in utility and industrial power distribution networks, including radial, looped and meshed distribution networks, with or without distributed generation. Jul 09, 2018 this video outlines the basic principles behind differential protection and is a sample of the full 2. Line current differential application on short lines. Line differential protection with relion 670 and 650 series.
The cable screen is earthed on both sides so that it effectively eliminates inductive interference the induced transverse voltage drives a charging current via the earth capacitance of the cable cores so that the transverse voltage to earth, shown in figure 2, arises. Paralleling cts for line current differential applications. Transformers and compensating coils in the protection range are also possible. Line current differential protection automation and control system. The l90 line differential relay and the l60 line phase comparison. Line differential protection substation automation protection and. Differential protection is selective, sensitive, simple, and fast, and it is commonly used to protect buses, transformers, generators, and transmission lines. In case of transmission line, implementation of differential protection requires a communication channel to transmit current values to the other end. Within a very short time this relay detects faults occurring within the zone to be protected by comparing the currents flowing between two measuring points, for instance the current on either side of a line or cable.
Differential protection what goes in must come out. Patel ge power management malvern, pa presented at the electric council of new england. Type test certificate, line differential protection red670 version 2. The siprotec 7sd828687 line differential protection have been designed particularly for the selective protection of overhead lines and cables with singleended and multiended infeed in mediumvoltage and highvoltage systems. Energy energy automation and smart grid protection siprotec 4 line differential protection. From a design perspective, the distributed nature of the line current differential system imposes limits.
Differential protection of a transmission line with digital. Performance problem of current differential protection of lines. Product guide red615 line differential protection and control. With its flexibility and the powerful digsi 5 engineering tool, the siprotec 7sd82 device offers futureoriented system solutions with high investment security and low.
Current magnitude and phase angle difference compensation. The following relays offer line differential protection. Speed is important for differential protection because it is the most selective protection. For longer transmission lines and subtransmission lines or even. The differential relay works on the principle of comparison between the phase angle and magnitude of two or more similar electrical quantities. Slide 1 content goals of protection definition of short lines challenges posed by short lines line current differential explained benefits of line current differential application example. Transmission line protection by pilot wires pilot relaying is limited to 30 to 40 km in rout length.
This section includes the following overviews of the sel311l relay. Problems and solutions david costello, jason young, and jonas traphoner, schweitzer engineering laboratories, inc. This is simply a differential protection scheme applied to feeders. Several differential schemes are applied for protection of line but mess price voltage balance system and translay scheme are most popularly used. Sel311l line current differential protection and automation. An alternative principle for line protection that is quickly becoming the norm is differential protection. There are several methods available for the protection of transmission and distribution lines 69. However, a threeterminal line may affect line current differential protection schemes if outfeed conditions occur during internal line faults. The differential relay works on the principle of comparison between the phase angle and magnitude of two or. Numerous computing were done to simulate the differential protection system on the underground cable transmission line 420 kv along the 58. The amplitude and phase angle of the fault current in photovoltaic power plants pvpps are significantly influenced by the control. Also, if used, it should be noted that the line differential backup protection schemes are subject to the same type of complexities.
A new approach to current differential protection for. From a design perspective, the distributed nature of the line current differential system imposes limits on the amount of data that can be. Sel411l line differential relay testing procedure 1. In figure 1 an example of a differential protection for two pilot wire cores telephone twisted pair is shown.
This addendum lists a number of information items that appear in the instruction manual gek1210a revision m2 but are not included in the current l90 operations. If the net difference equal zero, it means no fault exist. Application of the line differential protection scheme. Pdf advanced line current differential protection with reduced. Transmission line differential protection based on. Busbar protection busbar differential protection scheme. Wide area differential protection based on iec 61850 is presented in 10. Line current differential protection free download as powerpoint presentation. A failure in the line current differential hardware does not impact backup protection. In this type of protection the electrical quantities entering and leaving the protected zone or area are compared by current transformers c. Protective relay application guide prag gec alsthom.
Sel411l advanced line differential protection, automation. Abstract line current differential protection creates challenges for relay design and application. Line differential protection ied red670 free download as powerpoint presentation. The protection system should be set to operate in the presence of the outfeed condition. Current differential line protection setting consideration. Protective relay application guide prag gec alsthom free ebook download as pdf file. Differential protection of a transmission line with. A differential protection relay is defined as the relay that operates when the phase difference of two or more identical electrical quantities exceeds a predetermined amount. The sel411l provides differential protection with both phase and sequencebased operating elements for sensitivity and highspeed operation. Line differential protection modeling with co mposite current and volt age hamzah eteruddin 61 the relay commanded the breaker to trip at an equal period of time i.
Pdf line differential protection modeling with composite current. Transmission line differential protection function is one of the most important protection of transmission lines which should issue trip signal without any delay in. The complexity of protecting threeterminal transmission. Principles of differential relaying my protection guide. Line current differential relay response to a direct. The scheme of busbar protection, involves, kirchoffs current law, which states that, total current entering an electrical node is exactly equal to total current leaving the node. Transmission line protection principles ge grid solutions.
Apply the sel411l for complete protection and control of any transmission line. A sensitive current element in series with the highimpedance element is calibrated in volts based on the voltage drop across the internal impedance. High impedance busbar differential protection will not work properly if the cts are not sized correctly for the connected circuit. Pdf on feb 16, 2018, hank miller and others published modern line current differential protection solutions find, read and cite all the research you need on researchgate. Pdf line current differential protection creates challenges for relay design and application. Pdf line differential protection modeling with composite. The working principle of merz price balance system is quite simple. Principles of differential relaying introduction power systems divided into zones of protection e. View and download abb red670 product manual online. Sep 08, 2016 general scheme of differential protection 6. Technical manual, line differential protection red670 version 2.955 208 994 1133 492 629 948 1370 898 1154 1115 412 1124 1349 457 360 1505 1202 146 295 1430 570 1310 820 561 70 503 1218 759 105 1336 481