Rod Hughes Consulting General Web Site	Applications Home	Innovations and Solutions Home	A bit about Rod Hughes	Link to this page... The URL in the browser address bar is volatile and may be broken at any time. To obtain a link to this page, click the <<Share>> button top-right of the screen.

Note - if the navigation pane on the left of this window is not visible, click the 2-pane icon on the top bar

One of the key requirements for any critical real-time automation signals is the overall time for the decision of one function to be taken into use by the operation of another function.

Protection systems sometimes have extremely fast Critical Fault Clearance Time requirements. As an example, the Australian National Electricity Rules define the total fault clearance time limits as follows: (click image to enlarge)

Taking into account original fault detection, protection operation time, time to detect failed CB, time to CBF element to operate and finally time for the upstream CB to operate. Hence the time for messages to be passed from one function to another can be critical and must take into account total network latency IED message sending and receiving processing.

Whilst the Standard Part 5 refers to times "in the order of a quarter cycle", it is not really tied to the 20 ms or 16.67 ms period of a 50 Hz 60Hz cycle.

It is to do with ensuring that the performance of the LAN based signals is faster than wire based connections.

For wire based systems, IEDs with a physical relay output take 3-10 ms to operate the actual output relay.

IEDs with opto inputs have de-bounce filters etc which can also have 3-10 ms delay.

We just never bothered to identify these times when evaluating relay overall performance.

Bearing in mind that the same signal being sent from a Logical Node to another Logical Node now has to go through the outgoing stack and the incoming stack at the other end, plus through several LAN switches in between, it is important to maintain that level of performance or better - as function operation t function operation stacks and network included - than the wire based schemes.

Contact Me

Email Me

A phone call is nearly always welcome depending on the time of night wherever I am in the world.
Based in Adelaide UTC +9:30 hours e.g.

April-September	Noon UK = 2030 Adelaide
October-March:	Noon UK = 2230 Adelaide

Mobile + 61 419 845 253

Extra Notes:

Disclaimer

No Liability:
Rod Hughes Consulting Pty Ltd accepts no direct nor consequential liability in any manner whatsoever to any party whosoever who may rely on or reference the information contained in these pages. Information contained in these pages is provided as general reference only without any specific relevance to any particular intended or actual reference to or use of this information. Any person or organisation making reference to or use of this information is at their sole responsibility under their own skill and judgement.
No Waiver, No Licence:
This page is protected by Copyright ©
Beyond referring to the web link of the material and whilst the information herein is accessible "via the web", Rod Hughes Consulting Pty Ltd grants no waiver of Copyright nor grants any licence to any extent to any party in relation to this information for use, copy, storing or redistribution of this material in any form in whole or in part without written consent of Rod Hughes Consulting Pty Ltd.

This is general information on technology applications

Applications Home
Go To Innovations and Solutions Space
Go To Dashboard
Go to www.rodhughesconsulting.com

Chat to me on Skype?:

Search this topic

Extra Notes:

Collapse all Expand all Collapse all

Extra Notes:

Collapse all
Expand all Collapse all