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Power Planning


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Are there any options or methods in the ConnectCad work flow to document power planning. 
 

I’ve used the spotlight side power planning but this isn’t always practical.

 

Attached is how I document the power to show the flow through the schematic. Is there a way to trace the route that this goes through to the end device; showing which devices are connected to which phase and ultimately calculating the power draw on each phase?

 

tk

eec8b1b8-6a6a-473d-a7be-bcc87d0c6490.jpeg

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I've thought about this as well. With a few custom records and scripting, it wouldn't be too hard, but wouldn't be as slick as something coded at the SDK level and/or added by VWX. At the moment, I would mainly be interested to allow devices to be assigned to phases and a named supply (easy with a record), and for a worksheet to summarise the demand on each phase of each named supply. That's fairly easy. But to track the design current through each protective device is quite a bit more!

 

One challenge is that ConnectCAD is designed as line-per-signal, whereas your drawing above is line-per-wire. I've certainly been tempted to use it in that way for designing mains schematics, since the nearest available tool (that isn't a full electrical design package like Amtech Pro Design) isn't great. But the challenge comes when one mixes approaches in the same file - if one has other devices and circuits in the file where each line represents a signal, it all gets confusing very quickly.

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  • Vectorworks, Inc Employee

What I love about this forum is how you all keep independently discovering the topics I'm working on 😄. As Simon says this is not too hard to do at the basic level. However, power planning very quickly turns from design to modelling. And those are two very different things. In your question aggregating loads came up almost immediately. Propagation of loads back to power sources involves ConnectCAD devices "knowing" what they do internally. And right now devices are just a named collection of sockets. That simplicity is by design - it makes creating devices super-easy. But imagine if every time you wanted to create a device you had to define the relationships between the sockets? Your day would never end!

 

My challenge is to find a way to do this without making everyday design work harder. And not just for power but for every signal.

 

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Very interesting to know it is in the pipeline. I do see the challenges you describe though. 

 

Mmmm, yes an no on the line-per-wire. I think we can safely assume that neutral and earth will be wired in and we can see this as the signal "L1" 

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  • Vectorworks, Inc Employee

@tk_

10 minutes ago, tk_ said:

I think we can safely assume that neutral and earth will be wired in and we can see this as the signal "L1"

For a knowledgeable user who is aware of the assumptions he is making, I would agree with you. Though I wonder how the practices followed in the US involving wiring appliances across phases would fit in with this? Neutrals are often undersized on the assumption of proper phase balance etc. Would we need to be alert to a possible overloaded neutral? Designers inevitably rely on the results obtained from these models even though the small print in the EULA tells them not to. So as Vectorworks it's not so easy for us to release an electrical model that is incomplete and might fail to predict a real-world problem.

 

However I am very interested in discussing this maybe we can find a solution.

 

Conrad

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Yes I am approaching this from a UK standards point of view. I do a lot of work in the US though and I've just started thinking about the world of using L1,L2 to get 208v and what not.

 

I guess there is also no way of utilising the spotlight power planning tools in ConnectCad?

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  • Vectorworks, Inc Employee
18 minutes ago, Conrad Preen said:

Neutrals are often undersized on the assumption of proper phase balance etc. Would we need to be alert to a possible overloaded neutral?

We almost always use the same size wire for both ground and neutral in entertainment via rented temporary cable sets.

When needed, USA power distributors are available with double neutrals. With the increased use of gear that causes phase harmonics, which throw balances off, the neutrals are carrying more power than many electricians are used to dealing with. It's becoming more common to meter the neutral and adjust the neutral wire size/need.
 image.png

 

In a 208V 3-phase electrical system, current can be present in the neutral wire due to the imbalance of loads across the three phases. In a perfectly balanced system, where each phase carries an identical load, the currents in each phase would cancel each other out in the neutral wire, resulting in no current. However, this ideal balance is rarely achieved.

Here's why current would flow through the neutral wire:

  1. Imbalanced Loads: If the electrical loads connected to each of the three phases are not equal, the differences in current will not completely cancel out, resulting in a net current flowing through the neutral wire. This is common in the entertainment industry, where lighting, audio equipment, and other devices may not be evenly distributed across the three phases.
  2. Harmonics: Electronic equipment like LED lighting, dimmer packs, and audio amplifiers can introduce harmonics into the electrical system. These harmonics can cause neutral currents even if the fundamental loads are balanced because they do not cancel out like the fundamental frequency.
  3. Single-Phase Loads: In many practical systems, single-phase loads are connected between one of the phases and the neutral. If these loads are not evenly distributed among the three phases, there will be a current in the neutral wire. We have several distributors offering 120V & 208V power from the same box. Thus, the 120 uses the neutral, and the 208 supposedly does not.
  4. Switched Loads: In an environment like a concert or show, loads can be switched on and off frequently. This can lead to transient imbalances and varying neutral currents as different equipment is energized or de-energized.

It's important for electrical systems to be designed to handle the potential neutral current safely, as excessive current in the neutral wire can lead to overheating and pose a fire risk. 

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  • Vectorworks, Inc Employee

Spotlight power planning is not integrated with ConnectCAD. We are working on it.

 

I also grew up in the 220-240 volt world so I find the antics of our US counterparts hair raising! But this is our reality.

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Thanks Scott!

 

I think you have just excellently summarized the need to consider ALL conductors in any electrical model. As Vectorworks we cannot do less. So everyone will have to be a bit patient while we get this worked out.

 

C

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  • Vectorworks, Inc Employee
14 minutes ago, Conrad Preen said:

I find the antics of our US counterparts hair raising! But this is our reality.

Oh... Here's one that has surprised my EU colleagues here at VW.

Dimmer Doubling from ETC. Single cable, TWO DIMMING circuits. I used these in a theater with only 12 circuits to the front-of-house cove position to give me 24 dimming power circuits. Great device.
 

From ETC:

"Dimmer doubling uses the ability of a SCR dimmer to separately control the top and bottom halves of the voltage waveform. A dimmer doubler uses a high power diode arrangement to split the output of the dimmer into two halves, controlling two separate channels. This allows a single power cable to control two lights, but special 77V lamps must be used.

ETC's Source Four fixtures have a keying pin arrangement to prevent 77V lamps being accidentally inserted into 110V or 230V fixtures. Dimmer Doubled circuits typically use NEMA L5-15P connectors to differentiate them from 110V stage circuits.

Dimmer doubling is only supported on US (110V 60Hz) power types."

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