Cap Monitor Q&A - 11.29.10
We need to label all the diagrams as “Patent Pending”
How does it work?
The capacitor monitoring system incorporates a standard CT rated 120V meter to measure neutral current on a fixed capacitor bank. The meter measures both the neutral current and the voltage at switched locations. The meter is fitted with a communication module that enables Utilities to read the meter remotely. The type of communication module varies based upon the desired collection method for the location. The capacitor monitor will work with any RF enabled meter or meters that use power line carrier communications. By analyzing the data collected from the meter, the health of the capacitor can be determined.
What are the major components of the unit and what do they do?
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CT – measures the current on the CAP bank neutral.
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120V CT rated AMI meter – stores the reading and transmits the data to a database.
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Meter Adaptor - The meter adaptor houses the pre-wired CT and provides connection point for the meter.
What are the key advantages?
The system is not dependent upon any one communication system. Any type of communication module embedded in a meter can be used. The 120V used to power the meter allows power line carrier communication systems to be utilized. Communication modules for meters cost less than communication models designed for other applications.
How do I monitor the signal?
AMI System with hourly data.
Will the unit affect my current polling signal?
The Monitor could help the AMI system because it is approximately 30’ above ground. This makes a great “Repeater”.
Who is currently using the units, how many?
Georgia Power has deployed 50 for 2010 and plans to install 5,000 for the first half of 2011.
Will it void any warranties in my existing capacitor equipment?
The device can be added to locations with existing capacitor controls without requiring any modifications to the CAP bank or the control.
What type of AMI systems will it work with?
Any AMI system. The system is not dependent upon any one communication system. Any type of communication module embedded in a meter can be used. The 120V used to power the meter allows power line carrier communication systems to be utilized.
Communication modules for meters cost less than communication models designed for other applications.
What types of meter will it work with?
The capacitor monitoring system incorporates a standard CT rated 120V meter to measure neutral current on a capacitor bank.
Will the unit work in a substation?
Yes. This process will work any location to measure neutral current if the meter can communicate to the AMI system.
Will I need special connectors to install the device?
No. Installations use standard connectors and hardware (Butt splices, lag bolts).
What primary voltage / power requirements will the unit work with?
Any. The CT is connected to the neutral where the potential is zero.
What types of transformers will the unit work with?
Any supported by the meter you choose. Most switched capacitors have a small 120V transformer for powering the control.
How do you handle multiple banks of capacitor on the same pole?
Either the neutrals of both banks are monitored with two units or the joined neutral could be monitored.
Would a lighting strike affect the unit and meter?
By having the neutral current to pass through a CT instead of directly through the meter, the probability of damage due to surges is greatly diminished.
Is the unit fused?
No. The voltage source is normally fused.
How the unit is installed?
- What tools are required?
- Hammer, knife, crimping tool
- Are any extra materials required?
- Splices lag screws
- How much time does it take to install?
- 1 – 2 hours
- What special training is required?
- None. Very simple spec.
- Are technical drawings available?
- Yes.
What amp range will the unit work with?
High amperage installations, such as substation banks, might require a different CT ratio.
What is normal amp?
From our studies the normal circuit imbalance creates a small neutral current 1 to 6 amps. When a phase is off line, the current ranges from 20 to 40 amps.
What is the on-going maintenance?
None.
What is the est. savings i.e. payback?
Each unit will save any inspection cost. By analyzing the data collected from the meter, the health of the capacitor can be determined. Knowing the health of the capacitor has the benefit of eliminating manual inspections. The data can also be analyzed following thunderstorms or other conditions that may damage the capacitor system. The capacitors are a key component of Utilities Conservation Voltage Reduction (CVR) program. Keeping all units online during peak load conditions is critical to the effective use of CVR. There are also efficiency savings associated with operating the system and a near unity power factory
How is the AMI signal monitored and by who?
This will vary by utility based upon the type of AMI they have deployed.
What additional equipment is needed to monitor the signal?
None
What software is needed to monitor the signal?
A simple spreadsheet is all that is required, but using code to analyze the data will probably be desired if you have many banks to monitor.