Relay "WDZ-440EX" from Wiscom

<...tried contacting the manufacturer but no replies yet...> How bizarre.

Their telephone number is given on their website. The telephone is interactive, so one doesn't need to wait for <...replies...>!

Nope Tried calling them, but no answer either. I don't think my local time here matches their office hours, since I dont live in their country. Thanks for the recommendation... guru..

Phone them at their hours, then. Sheesh.

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I have no experience with this relay but I am certain that it does not measure pressure directly. There must be a pressure transducer that converts pressure to a voltage or current for this relay to sense pressure. Depending on the conversion of this transducer the 0-2 range could map to almost any pressure.

Standard nomenclature for a "63" relay is a switch closure for flow and/or pressure, typically from a Buchholz or Sudden Pressure relay. More than likely, but you'll have to verify, the settings are for different time delays before issuing a trip command. "0" is probably instantaneous, "1" and "2" may refer to two different inverse time curves (steep and steeper) or two different time delays in either milliseconds or cycles.

Your best bet is to contact the protection engineer that specified the relay. One thing's for sure, if it's not "your" piece of equipment, don't go pressing buttons at random (which it appears from your picture you already have)!

Thank u for the answer...so its actually time delay?

I did not say that, I said probably, because that's how some other vendors do it, and the product specs on the Witcom website "hints" at it, you'll have to do some of your own work and find out for sure.

I reaffirmed it. And its not time delay. Pic below.

Both pic are on the same menu (protection setup values), but is a different item in the menu. By the way there are 3 switches that act as pressure relay in the menu (switch 5, 6 & 7). Each with it's own time delay and pick up settings. Pic for switch 5 & 7:

the term "switch" in this case is just the name of the pressure relay (63) in my opinion. But the pickup value of each switch seems to correlate with each other. Switch 5 actuates the Alarm feature, Switch 6 activates the trip feature when the pickup value is reached, and Switch 7 activates the Off feature. here are the time delays for switch 5 & 7:

Please share your opinion as well on this topic.

If you buy anything fom China because it is cheap then you face such problems. No response and language problem.

what is the usual pickup values of a sudden pressure relay? What unit does it usually use (Kpa, psi, bar or atm) for the pickup values? can an under voltage trigger such relay?

Thank you for your support.

My feeling is these are logic multiplier relays as add on additional facilities for electrical interlocking with external circuits or relays. Please check in test mode whether these relays are operated from front panel and whether all its contacts are wired out to the terminal block of the relay as potential free contacts. Please also check whether each relay is programmable for ON/OFF delay timer.

A transformer 63 device is normally referred to as a fault pressure or sudden pressure relay. Bulkholz makes them as others do. Some work on the air space but the best ones work on the oil and look at the pressure wave. They operate on rate of rise of pressure not a given pressure. The chinese relay you specify does not perform that function as far as I can figure out, it only monitors the contact from the 63FP device. It then can communicate that information along with other information. A 63FP device should be wired to imeadiately trip all power from both sides of the transformer and have a lockout (86) device to force the user of the transformer to go to the transformer and make an evaluation. Normally when a 63FP device triggers, the transformer needs to have extensive testing including oil tests, gas in oil analysis, power factor of insulation, hipot, meggar, and most time draining and internal inspection. A 63FP trigger usually means the transformer needs rebuilding but re-energizing without checking can cause it to become just a piece of scrap metal or worse, a fire bomb that can burn for days and destroy a substation and much around it. It is a very useful devise and should be tested annually.

A few years ago, I witnessed a transformer that had tripped on 63FP while other testing was performed in a substation by a competitor for a major southwest utility. The engineer told them to re-energize without testing. The transformer exploded and burned for more than a week. A fire department early on that was not experienced tried to put it out with water and the second explosion sent 3 people to intensive care. Although I was not called initially, when I was, I called a local air force base that had equipment to make a large enough attack with foam used for runway fires to prevent air from reaching the fire which put it out. Luckily there was only desert around and no residents within 5 miles. I felt the explosion and saw the fire from my house 7 miles away. The substation was out of commision for more than a year.

The 63 relay tripped when there was a fault (undervoltage) from the grid meaning from outside of the power plant, outside of it's protection zone. There were two others dry type transformers that tripped in that incident. Those two tripping (63 relay was activated) were to be expected, because they were supplied from the grid through a station service transformer. But the third dry type transformer weren't supposed to trip. because it was supplied from the generator through a unit auxiliary transformer, and doesn't have a connection to the grid. yet it still tripped. This third dry type transformer supplies the electrostatic precipitator (ESP) of the unit. Attached to the same 6.3 kV busbar as the third dry type transformer, there were two other dry type transformers and some big motors. But those didn't tripped in the incident. So why did the ESP dry type transformer tripped (when it has no connection to the grid fault) and why was it the only one that tripped (aside from the other two that were supplied from the station service trafo) is still a mistery.

Now we are completely off track. Is the relay provided for dry type transformers? Are the 63 elements already wired to external devices? If so, what is preventing you from referring to SLD's or physically tracking at site to see to which protection elements these are wired to. That will give us some direction to do proper post mortem. Understanding the interlocking logic of 63 element in light of stated under voltage conditions in the grid may shed some light on why selective tripping occurred. Can you please check and revert.

Hello again, this is the wiring diagram that i found on the manual of the relay:

This is what the manual explain about "switch protection (63)" relay function:

Switch protection is mainly used for light gas, heavy gas or temperature protection. The drive power of switch inputs which is normal opened contacts is supplied by the equipment (+24V). Corresponding non-electrical-quantity protection starts up when outside contacts close. The equipment provides three normal opened contacts non- electrical-quantity switch inputs. Each switch protection can choose trip or alarm. Action time can be independently set.

For now this is what I can get. Stilll don't get why an undervoltage can cause this relay function (63) to trip. Does anyone know anything regarding this.

Quote:Still don't get why an undervoltage can cause this relay function (63) to trip. Does anyone know anything regarding this

A properly installed 63FP with a manual lockout relay will not give a false trip. The relay you have described is taking that output and sending it on and can give a false trip due to a power surge. The description that is given in the instruction book leads me to believe that the relay manufacturer does not know much about relay techniques. I would avoid this relay and manufacturer if you have not yet purchased. If you have purchased it, I would consider doing away with it. I think you may have a lot of grief from the use of this relay. Other better relays are available. That has nothing to do with the 63FP and lockout which should simply be a contact input to the relay you refer to.

"The relay you have described is taking that output and sending it on and can give a false trip due to a power surge."

Please explain this statement. As is not clear to me what do you base this statement on?

What this means is code 63 (ANSI) is used for mechanical protection (non electrical) like Bucholz's, OTI, WTI, or oil surge. These are standard protection features for any transformer protection relays and are in no way connected to tripping by under voltage condition. You will need an experienced power system analyst at site to decipher the sequence of events or you should be in a position to share all pertinent data (which i am not sure whether you are privy of) with this forum. Without relevant data like datalogger or SCADA printouts, to quote RAMConsult, "we are at an impasse".

We are at an impasse here, you have a copy of the manual but we don't. From what I've read this "relay" is actually a microprocessor based transformer management system that tries to be all things to all users.

If you truly want to understand how it works take it to a test bench, power it up, and monitor all the output contacts with LEDs. Then start working your way through every level of every menu and try to characterize what all the various settings in each submenu do to the output state of the LEDs. It shouldn't take you a day to fully understand what you have in front of you and how to make it behave the way you want. Then find an experienced relay engineer to help explain what the right settings should be and which ones to ignore. Keep good notes and let us know what you discover.

Using test and experiment protocols to decipher any device is not what the internet promotes. Testing requires cogent thought. Besides, we provide a convenient excuse when failures happen.