hv controller

[snapper]

hi people am new to this forum . am running a fortis montana turbine on grid tie . and would like to make a controller am hoping you can piont me in the right direction, what am trying to do is make a controller that at around 350vdc to 380vdc  can turn on my dump load . some type of relay or contacts . was looking at plc relay but not to sure of what to use thanks s

[rickysmartz]

Hi Snapper,

I use an Omron K8AB-VS which is a voltage sensing relay, 470v max and settable down to 50v. Its a normally open unit
and is used to control a Schneider 15963, normally closed 3 phase relay. Good units, not cheap but no problems with them.

If you use something like this make sure you get the normally closed 3 phase 15963 version which gives you 'dumpload on' in a grid fail situation.

You dont need the complexity and extra expense of a PLC unless you want other controls also.

The Omron has settable hysteresis and a timer to avoid 'chatter' as well as some other simple adjustments.  Its perfect for wind turbine control.

Total price in Europe € 120.

Richard

[Jon Miller]

I was going to say the SMA protection box but that is not cheap and this relay seems like a cheap option if it works.

Are you planning to grid tie or water heating?

Regards

Jon

[snapper]

thanks guys am using a eurora interface at min but the dump is set to high in it . can you explain to me what is a settable hysteresis and what does the timer do avoid chatter sorry what is chatter thanks s

[fabricator]

Hysteresis is used to provide a lag in a control between the on or off state, some controllers use "Fuzzy logic" to learn where the hysteresis should be in a given system, not sure if the Omron uses that or not, the hysteresis would prevent rapid on off switching which is also known as "chatter".

[rossw]

thanks guys am using a eurora interface at min but the dump is set to high in it . can you explain to me what is a settable hysteresis and what does the timer do avoid chatter sorry what is chatter thanks s

Hysteresis, in the context you're using it, is a technique to increase stability in a system by using a different threshold depending on the direction of change.
For example, if you have a relay that you want to turn "ON" if the voltage is above 13 volts, and "OFF" if below 13 volts, when the voltage is right on 13V - any noise, even millivolts worth - will cause the relay to cycle rapidly between on and off.

With hysteresis, the "nominal" voltage might be 13V, but the relay may not turn "ON" until 13.1V, and off until it gets to 12.9V. So sitting at 13V the relay will never chatter. Is 13V "on" or "off"?  Well, it depends!  If the voltage had been at 13.5V, and has fallen back to 13.0, the relay will be on. If the voltage HAS been 12V and has risen to 13.0, the relay will be "off".

Hope that explains it

[snapper]

yes that makes total sence. what i cant under stand should the omron k8ab sencing relay not be normally closed to power the other relay nc to open the contacts other wise the turbine would be in dump all the time never get started then when vdc get to say 350vdc and sencing relay open other relay closes to dump no power defaults to close am i write or wrong thanks s

[niall2]

hi Snapper

i,ve definetly no experiance of these relays ...but i think if the omron sensing relay activates at a certain cut off point (with Hysteresis) it sends a signal to a "bruser" relay ....depending on the type of relay you could wire the contacts to be either active or dormant ...leave the diversion load open or shut  ....shut down is the option ...depending on the relay options it might actually "latch" as well....(or lock on)