bus zone protection is a unit protection meaning a protection with a restricted zone therefore does not need to be coordinated with other time based protections . Course Overview. This course is intended to assist the user to find their way around the schemes that are supplied by Powertech SI to ESKOM. The schemes . When we examine electrical protection schemes, the best place to start is with electrical bus protections – overcurrent, differential, undervoltage.

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How important are English communication skills in Gulf zone areas? However, it permits different CT ratios. Please log in and try again. You can’t add content on Bayt. John, the basic protection scheme used is measurement of differential-current. There is no selectivity using check zone. It is based in simple circulating current principle that during normal load conditions or external fault conditions, the sum of currents entering the bus equals the sum of the currents leaving the busbas, i.

Two other items are indicated in the diagram. By Mohammad khoshkholgh Dashtaki at Sep They are of two types from point of view of principle of operation: A simple differential protection scheme is shown in the figure below. Danger zone protecttion food processing apply where the chemicalbiochemicalmicrobiological reaction are at h Ir relies on the feeder currents in the busbar.

What is the difference between check zone and bus zone in busbar protection?

The CT connected to the corresponding zone will give initiation to the particular zone trip relay. That is, if any of the incoming supply conductors carry fault-current but none of the outgoing feeders do, then the supplies are tripped. It is a very simple, reliable and fast operating scheme provided CTs and stabilizing resistors have been selected properly for stability against operation by through fault currents outside the zone of operation. Unfortunately, pprotection answer you are trying to submit has already been added.


In this type, the busbars can be sectionalized to identify the fault in that particular section. In such a case duplicate A and B protections cannot protectoon used. Please make sure that your answer is written in the same language as the question. The desirable features of bus zone protection include the following:. To exclude a word, precede it with a “-“, as follows: The owner has blocked you Answer should contain a minimum of 25 characters.

From the point of view of zones of protection they are classified into discriminating and check zone protections. Additionally to this where the design of the switchboard allows for a bus section switch which divides the switchgear into two sections.

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The Basics of Electrical Bus Protections

A bus fault tends to be appreciably more severe, both with respect to the safety of personnel, system stability and the damage to the equipment’s. Differential Protection of Transformer. Difficulty arises from the fact that there are many pit-falls.


In other words, the ratio of the relay current during an internal fault to relay current during an external fault is greater if the impedance of the relay is higher. Select the categories for which you would like to see messages displayed Apparently it is justified by the fact that a busbar fault is very unlikely and even if one should occur it would be cleared by another protection. Disconnectors positions are not required.

It’s usefully because it prevents external faults to be considered as a busbar fault. No current will flow in the overcurrent relay. Generally always Circuit Breakers are included in the zone of Busbar protection.

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Premium Membership Premium membership gives you an access to specialized technical articles and extra premium content electrical guides and software. Then only it will protect the system entirely from wherever the fault occurs. My Question is New. For low-voltage buses Mainly the selection of zone should be overlapping each other. That is a current in the relay indicates a fault within the protected zone and initiates opening of the generator breaker CB 1 and CB 2 and each of the line breakers CB 3CB 4 and CB 5 including the bus breaker CB 6.

Irrelevant to Specialties or not an answer. ISO – Record Protection: