Knowing of fault type in power system

Thread Starter

mnobeidat

Joined Dec 20, 2016
20
Hi
I searched for applications of neural networks in power system and found that it's used to distinguish between different types of faults.
Why is it important to know whether the fault is a line to ground or double line fault or whatever it can be if the protection system will trip all of three phases despite what the type of fault occurred?

*note: I don't know what is the appropriate forum to post this thread in, so please, move it to the most appropriate one.
 

Reloadron

Joined Jan 15, 2015
6,059
Why is it important to know whether the fault is a line to ground or double line fault or whatever it can be if the protection system will trip all of three phases despite what the type of fault occurred?
While I am not sure what you are asking in a poly phase system it is very important to identify a fault. Just as an example looking at a 480 VAC Delta configured ground fault system:

3 Phase Ground Fault.jpg

All of the lamps will glow with a light intensity, not bright. If any of the 3 phases develops a short to ground, be it through a motor, a heater element or any other short to ground the lamps on the shorted phase will extinguish and the other bulbs will glow more brightly. A delta configuration the voltage is measured phase to phase but there is always a residual floating voltage between any phase and ground. The above will identify what is known as a "Ground Fault". If we have a Phase A short to ground and ignore it and a subsequent Phase shorts to ground it becomes the same as a full phase to phase short. We use fault detection systems which identify the nature of the fault.

There are also phase monitors for Phase Loss so if a phase fails or is lost things like motors, compressors and other sensitive equipment can be shut down. This can prevent damage to large motors.

There is also under and over voltage monitoring. The phases should have a balanced voltage and a user needs to be aware of any under or over voltage conditions and take any corrective actions.

Again, I am not sure exactly what you are asking?

Ron
 

MisterBill2

Joined Jan 23, 2018
9,266
While I am not sure what you are asking in a poly phase system it is very important to identify a fault. Just as an example looking at a 480 VAC Delta configured ground fault system:

View attachment 149104

All of the lamps will glow with a light intensity, not bright. If any of the 3 phases develops a short to ground, be it through a motor, a heater element or any other short to ground the lamps on the shorted phase will extinguish and the other bulbs will glow more brightly. A delta configuration the voltage is measured phase to phase but there is always a residual floating voltage between any phase and ground. The above will identify what is known as a "Ground Fault". If we have a Phase A short to ground and ignore it and a subsequent Phase shorts to ground it becomes the same as a full phase to phase short. We use fault detection systems which identify the nature of the fault.

There are also phase monitors for Phase Loss so if a phase fails or is lost things like motors, compressors and other sensitive equipment can be shut down. This can prevent damage to large motors.

There is also under and over voltage monitoring. The phases should have a balanced voltage and a user needs to be aware of any under or over voltage conditions and take any corrective actions.

Again, I am not sure exactly what you are asking?

Ron
The reason to know what type of fault has occurred is because mostly power distribution systems are supposed to be reliable and so quickly determining faults and clearing them is a considerable value. A neural network system might be made to function but I would not consider it the best choice for speed and accuracy. Discreet hardware detection systems would be faster and not need any programming. The big thing is that in fault detection systems the general flexibility is not needed and really will provide no benefit, since the types of faults are limited and well defined. Also, most computer system flaws are software and the hardware method does not need software. THAT is a HUGE benefit.
 

Reloadron

Joined Jan 15, 2015
6,059
The reason to know what type of fault has occurred is because mostly power distribution systems are supposed to be reliable and so quickly determining faults and clearing them is a considerable value. A neural network system might be made to function but I would not consider it the best choice for speed and accuracy. Discreet hardware detection systems would be faster and not need any programming. The big thing is that in fault detection systems the general flexibility is not needed and really will provide no benefit, since the types of faults are limited and well defined. Also, most computer system flaws are software and the hardware method does not need software. THAT is a HUGE benefit.
While I agree I still don't get the point of the thread? Would there be a question or is the thread starter merely stating a fact or facts? Here in the US poly phase power is delivered in a few ways with a focus on either WYE or DELTA. Regardless of the distribution system it is important to have fault detection for any of the things I mentioned and a few more. During design time the designer needs to consider which characteristics he or she wants to monitor and find suitable hardware to do the job. All of that is a simple given in the design process so I ask again, are you asking a question or stating a fact? All of the panels for any control I designed included hardware solutions and downstream of any main disconnects or fusing. I also sought to use different power for my fault detection when possible.

Ron
 
Last edited:

Thread Starter

mnobeidat

Joined Dec 20, 2016
20
While I agree I still don't get the point of the thread? Would there be a question or is the thread starter merely stating a fact or facts? Here in the US poly phase power is delivered in a few ways with a focus on either WYE or DELTA. Regardless of the distribution system it is important to have fault detection for any of the things I mentioned and a few more. During design time the designer needs to consider which characteristics he or she wants to monitor and find suitable hardware to do the job. All of that is a simple given in the design process so I ask again, are you asking a question or stating a fact? All of the panels for any control I designed included hardware solutions and downstream of any main disconnects or fusing. I also sought to use different power for my fault detection when possible.

Ron
I am asking a question.
When a ground fault occurs the protection system will trip all of three phases. And it will do so for a line to line fault and three phase fault and double line to ground fault.
So the protection system will act in the same way no matter what the type of fault has occurred.
So, why would someone bother to record the type of each fault occurs in the system?
What benefits someone can get from knowing the type of fault?c
Sorry, I cannot be more clear than this. Hope you get it
 

Reloadron

Joined Jan 15, 2015
6,059
So, why would someone bother to record the type of each fault occurs in the system?
What benefits someone can get from knowing the type of fault?c
Sorry, I cannot be more clear than this. Hope you get it
The reason I would care is once I know what the fault was or is then it becomes easier to locate the fault specifically. If for example I lose a phase and can track that phase loss back to the specific sub I can look at my data for that sub and figure what went wrong. If on my 480 VAC 60 Hz I get a ground fault I can start isolating my feeders until the fault goes away. I chased one once and it was a shorted blower motor on the building roof. Facilities maintenance and engineering leads to knowing exactly where and what a fault is caused by.

Ron
 
Top