Over Current & Differential Relay

[shahidbinlatif]

Dear all
Can some one help me i wanna make a Over Current & Differential Relay with Microprocessor AT8051

 

[goldsmith]

Dear shahidbinlatif
Hi
What do you mean by " Over Current & Differential Relay " ? if you explain it , perhaps i can help you .
Best Wishes
Goldsmith

 

[shahidbinlatif]

Dear Goldsmith
Hi
i want to make a over current relay i have to need schematic and 89C51 coding.
i have a little bit idea if u understand our circuit consist of CT's PT's when the current exceed over the given setting relay operate and display out like that i have to need.if u have an other idea please inform me

 

[goldsmith]

Hi again . It is pretty simple . but can you tell me about your maximum values ? for example how much current and voltage you are referring to ? is that AC or DC ? if it is AC , how much is it's frequency ? though , how much precision do you need ?
Best Wishes
Goldsmith

 

[shahidbinlatif]

Dear
i have to need AC Over Current & Differential Relay with these specification
CT 1amp to 5amp
PT 110
Frequency 50
Thanks for hel

 

[goldsmith]

Hi again
So , a simplest way , in my idea , is : amplifying the current sample and then rectifying and filtering it , and then , comparison between that and a reference voltage . and then a simple transistor , as a driver for your relay . thus , if the current exceed from allowed value , the relay will cut it !
Best Wishes
Goldsmith