Abstract
PMI has just introduced a major redesign of the Guardian meter socket power quality analyzer. This white paper will focus specifically on the new Cell Guardian recorder and cover the new features that are not present on the older model. These features include cellular and WiFi communications, e-mail and text message notification, dramatically larger stripchart and waveform memory, waveshape triggering for waveform captures, CBEMA event recording, and access to PQ Canvass.
Cell Guardian Basics
The Cell Guardian (Figure 1) is designed for use in a 200A residential meter base with the existing revenue meter. The new Cell Guardian is completely redesigned from inside out. Like the older Guardian, it has the ability to record standard measurements like voltage, current, power factor and harmonics to the 51st, but now can capture CBEMA/ITIC events and Advanced Waveform Capture as well. With up to 1GB of storage, you can collect months’ worth of data, ensuring you have the whole picture.
Cellular Communications
Now with cellular communications you can save time and money by moving from investigation site to investigation site without ever having to bring the Cell Guardian back into the office. The cell features allow viewing of the data from the office without the need to go to the field to retrieve the data. With the cell connection, recordings can automatically be sent to PQ Canvass or downloaded to ProVision.
Since the data can be viewed at any time from the comfort of the office, problems can be discovered earlier. After seeing data, if further investigation is needed, you can change the recording settings without having to go to the location. The ability to see the data and change the settings from the office can greatly decrease the troubleshooting time and save the expense of having to roll a truck to do these functions.
PQ Canvass Integration
The Cell Guardian can stream recorded data as it’s gathered during the recording session to PQ Canvass. No longer is there a need to wait until the “end” of the recording session and download the entire recorder memory. Simply log into PQ Canvass and view all data gathered up to the present time.
PQ Canvass has been designed to support a wide array of devices and screen sizes. This allows you to manage your devices, browse recordings, and even view live waveforms easily, whether at your computer at the office or with your smart phone or tablet. See the white paper “Introduction to PQ Canvass” for more information about PQ Canvass.
Alerts
One of the key features of the Cell Guardian is exception-based triggered alerts. Alerts can generate e-mail and text message notifications when configured with PQ Canvass. These are the same alerts generated by Revolutions and Boomerangs. The alert notification distribution system revolves around a number of components. Two of these critical components are Events and Alarms.
An Event is an occurrence which is just what it sounds like – a single event that, when it occurs, generates data transmission to the PQ-Canvass system which in turn generates a notification for all those who have been registered to receive a notification for said event. Events do not necessarily span an amount of time – each event will trigger an update packet to PQ-Canvass and, if there are any registered notification recipients, they will be notified.
An Alarm is a state that a device may be in. These states may span long periods of time (hours or even days) or may be as brief as just a second or two. Users who have created distribution lists to receive Alarm notifications will be notified when the device enters an alarm state and when it exits an alarm state. This method of notification was selected to prevent multiple notifications from being sent for a device that remains in an alarm state for a prolonged period. The exception to this rule is the “no alarm” series of alarms – these are all similar to events in that they are only triggered once, when a device falls out of its respective alarm state (voltage, current, frequency, etc). Adjustable alarm thresholds and configurable notification lists make alerts a powerful feature that saves time searching for problems and allows much quicker reaction times when problems arise. See the white paper “Configuring Alerts with a Guardian in PQ Canvass” for more information about configuring alerts with a Guardian.
Enhanced Waveform Capture
The enhanced waveform capture features of PMI’s Revolution recorder are included in the Cell Guardian. These enhancements include THD triggering, Waveshape triggering, and cross triggers for event capture.
Waveform capture is the highest resolution data available for PQ analysis, and is often crucial in solving tricky issues. With enhanced waveform capture and much more available waveform memory, the new Cell Guardian matches the Revolution for capture ability, and exceeds it in storage capacity. The new waveshape triggering feature allows for capturing oscillatory transients and other events that involve significant distortion on the waveform, but without large RMS changes. For more information about the Enhanced Waveform Capture, see the white papers “Waveshape Triggering for Waveform Capture” and “Optimizing Waveform Capture Triggering”.
Live Data
Live waveform can be viewed with ProVision and PQ Canvass at any time that the Cell Guardian has a cell connection. This allows viewing the data almost real-time from ProVision and/or PQ Canvass. Live data allows immediate access to the Guardian data. If a customer, whose residence has a Cell Guardian meter socket recorder, calls to say that their reported problem is currently happening, then the technician can look at live data to see what the Cell Guardian is reporting.
Figure 2 shows a live meter in ProVision.
Figure 3 shows a live Guardian waveform capture in PQ Canvass.
Figure 4 shows a live Guardian waveform capture in ProVision.
WiFi
WiFi is optionally available on the Cell Guardian which allows it to host a WiFi hotspot. This allows connections from laptops and iPads to view data and download devices without the need to attach the USB cable. This WiFi network may be disabled if not needed for certain installations.
Network Time Sync
The Cell Guardian can set its time from NTP (Network Time Protocol) from an NTP server. This allows accurate recording timestamps without the need to connect a PC to set the time.
Conclusion
The Cell Guardian meter socket recorder is a powerful tool for PQ analysis at the revenue meter base and it has features that are not present on the older Guardian recorder. These features include cellular communications, e-mail and text message notification, larger stripchart and waveform memory, waveshape triggering for waveform captures, CBEMA/ITIC capture, and access to PQ Canvass.
