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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Please refer to the litrature of MCAG. It can be seen that a high impedance bus differential relay can discriminate between internal and external faults better than the usual low impedance relay. If all Current Transformers,all having the same ratio are mounted on every circuit connected to the busbar and are connected in parallel then a fault external to the busbar will result in a balance of all CT currents which will not initiate the high impedance relay,but if the fault is on the busbar then the protection will operate.

Let me know if additional information is required! Moreover, the need for bus zone protection is highly felt because, the faults level at busbar is very high and the faults on bus-bar causes discontinuance of power to a large portion of the system.

Then the breaker will get trippped. Your use of this site is subject to the terms and conditions set forth under Legal Notices and the Privacy Policy.

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

How important are English communication skills in Gulf zone areas? Under normal and external fault conditions the voltages add up to zero, whereas for an internal fault there is a resultant voltage in the secondary circuit and the relay operates.


Leave a Comment Click here to cancel reply. Additionally to this where the design of the switchboard allows for a bus section switch which divides the switchgear into two sections. Two other items are indicated in the diagram. Disconnectors positions are not required. I hope this helps,let me know? Your subscription request is being processed. A special type protechion CT having no iron core, also known as the linear coupler is sometimes employed to overcome the difficulties of an iron cored CT.

Facebook Linkedin Google Plus Twitter. Please read those terms and conditions carefully. Select the categories for which protsction would like to see messages displayed On many installations busbar zone protection is not considered necessary lrotection its use is limited to important substations. Buuszone Password Remember me on this computer. High impedance and Low impedance types.

For low-voltage buses Try adding a different answer. Follow Upvote Report Question Comments 0. Protectoon Grounding Techniques Read: No current will flow in the overcurrent relay. However, it permits different CT ratios. To search the site, enter your search terms in the box labeled “search the site” and hit Enter.

John, I will protechion to explain what i know about busbar protection as i am not a protection engineer. Protectioj 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.

Go to the following web site www. If any fault, either a phase to phase fault or phase to earth fault occurs in the systems, the sum of these currents will not be zero and some current will flow through the relay and causes the relay to operate and isolate the faulty section.


A simple differential protection scheme is shown in the figure below. Please make sure that your answer is written in the same language as the question. What is the meaning of danger Zone while processing food operations?

Bus Zone Protection and Causes of Busbar Faults

My Question is New. This is standard notation that Amps in the primary will produce 5 Amps on the secondary. The desirable features of protsction zone protection include the following:. 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. Busszone Comments and Comments with Links will be deleted immediately upon our review.

One is the direction of CTs. Simple,in principle, but difficult to implement! Inter-lock over current protection to trip generator unit if bus-zone protection operates.

Foreign objects accidentally falling across fault current. For HV switchgears with more than one bus bars and switching isolators etc, the low impedance differential relay is used which is a costlier solution.

Biasing of differential relays improves the stability considerably; but is not a complete solution.