Trends in Next Generation Power Monitoring

Alan Katz, Product Manager for MCMS at Anord Mardix

Data center power monitoring has remained largely static over the last 20 years. Now with the advent of high-powered processors, some power monitoring has become “intelligent.” This development brings with it a host of beneficial new features that are helping to make data centers more reliable, including waveform capture, CBEMA ITIC monitoring, and common circuit creation. These new features are described below.

Data center power monitoring has remained largely static over the last 20 years. Now with the advent of high-powered processors, some power monitoring has become “intelligent.” This development brings with it a host of beneficial new features that are helping to make data centers more reliable, including waveform capture, CBEMA ITIC monitoring, and common circuit creation. These new features are described below.

Waveform Capture

Waveform capture is a function that automatically, in most cases, captures a high-resolution snapshot of voltage and current waveforms after a specific threshold is crossed (Figure 1). To be useful, these captures must incorporate pre- and post-event data, which requires a continuous rolling log. The system must be able to retrieve past data capture at resolution of at least 40 data points per cycle. It is also critical that captures be implemented on all current channels for multi-circuit / branch circuit meters.

The benefits of waveform capture include:

• Critical diagnostic data can be used to analyze faults, disturbances, and outages. A prime example is a disturbance caused on the load side of the bus that propagates throughout the bus and affects other critical loads. If waveforms are captured on each branch circuit or feeder breaker, it can be very apparent what circuit and potentially load was the culprit.
• Pre-emptive load failure analysis: Manual triggering of captures can be compared against benchmark captures to identify progressive anomalies in loads. This could extend to failing VFDs on pumps and chillers and even capture failing power supplies before they have a chance to affect the load. This analysis can also be automated using embedded AI script in the monitor to provide pre-emptive alerts about changes in load signatures.

Figure 1: Example of a multi-channel waveform capture on modern multi-circuit power monitor. (Image: Anord Mardix)

CBEMA ITIC Logging

The CBEMA / ITIC curve has been established as the acceptable voltage window for IT loads (Figure 2). Deviations outside this window have the potential to affect critical loads. Unfortunately, so many of these violations are transient and occur either too fast or too slow to be recognized as they extend from micro-seconds to minutes. Identifying deviations as they happen requires a monitor that samples voltage at fast as 40 kHz, which is beyond the capability of many legacy processors. The advent of faster processors is now bringing down the cost of making this level of monitoring a new standard down to the branch circuit level.

Having a power monitor that captures these often-unseen violations is essential in maintaining the integrity of the critical bus. To be effective, violation data needs to incorporate the duration, magnitude, and time of event. It also helps if the meter classifies the type of event, such as a sag, swell, transient, etc. By logging this data, any incidents can be effectively dissected to determine a root cause. More importantly, these events often go unnoticed until they affect the critical bus, thus active monitoring will often alert operators to precursor events before a situation becomes critical.

Figure 2: The CBEMA / ITIC “power quality envelope” creates a time-based window for acceptable voltage levels for IT equipment. Voltages outside the window are considered violations and need to be recorded. (Image: Anord Mardix)

Figure 3: An example of CBEMA / ITIC event logging where red dots indicate an event and are logged according to voltage magnitude, duration time, phase, and event type. (Image: Anord Mardix)

Common Circuit Creation

Figure 4: Modern Multi-Circuit meters have the ability to group circuits to express the total data for the circuit breaker as well as derive the neutral. (Image: Anord Mardix)

In the case of Multi-Circuit monitors, measurements are usually expressed as per circuit data meaning it is up to the BMS / DCIM to determine the total for any multi-phase circuit. To be effective, Multi-Circuit monitors must have some means of intelligently grouping circuits to present a total for the circuit breaker (Figure 4). This feature will also allow for the mathematical calculation of neutral without the need for a neutral CT; a method that is 100% accurate. Common Circuit creation also simplifies integration with BMS / DCIMs.

Alan Katz is Product Manager for MCMS at Anord Mardix.