Guardian Monitoring®

Round-the-Clock Monitoring with Expert Analysis

View monitor reports on Transformer Dashboard®, leverage five decades of SDMyers expertise to analyze that data, and receive practical recommendations of what to do next in the event of a fault.


With the Guardian Monitoring service from SDMyers you can enjoy all the benefits of round-the-clock monitoring combined with expert analysis from our engineering and diagnostic team. The G1 fault-gas monitor samples the oil in your transformer and reports that data directly to us. You can see this data too, via Transformer Dashboard. Our team of experts analyze those results, which include:

  • H2 level (ppm) & H2 Rate of Change (ppm/day)
  • Moisture in Oil (ppm)
  • Oil Temperature

Use round-the-clock data for improved analytics.
Our monitors transmit dozens of individual data points throughout a 24-hour period--hundreds more than with traditional sampling and analysis. We consider equipment type, fluid class, application, individual unit history—essential factors when assessing the condition of each unit on an individual basis. We compare these metrics against what we already know about your transformer.

Receive timely alerts if we discover a problem.
With the advanced G1 Gas Monitor hardware and our Transformer Dashboard®, combined with 50+ years transformer management expertise, SDMyers is here to watch over your most valuable assets. Regular analysis allows us to recognize faults quickly and alert you if that fault is critical.   

Avoid false alarms for greater peace-of-mind.
Each transformer is unique. We set limits based on the condition of each transformer in your fleet. This helps us avoid false alarms by setting parameters appropriate to each individual unit. These parameters are based on application, history, and overall health of your equipment. No more false alarms. We’ll only alert you if it’s urgent.


NOTE: Hydrogen gas buildup in transformer oil is an early indicator of incipient transformer faults and the Guardian Monitoring system is built to provide an alarm based on PPM Levels and/or Rate of Change (ROC), warning customers of potentially disruptive transformer faults and pending failures. The Transformer Dashboard receives this data from the Monitor and allows the customer to view that data, graph and/or receive alarm notifications.

FAQ 1 What are the features of Guardian Monitoring?

What are the features of Guardian Monitoring?

  • Hydrogen (H2) and moisture (H20) monitoring equipment
    • Modem and cellular communication included
  • Installation and set-up of equipment
  • Expert review of monitor data by our Guardian Services team
  • Alert, alarm and rate-of-change alarm management (We set the parameters)
    • Automated notification sent to our Guardian Services internal team for Power, Service and Alarm settings. If an alarm is generated, the Guardian Services team is notified. The team determines whether it is necessary to alert the customer.
  • Help in managing and executing the next step in the event of a fault
  • Guardian Services reporting with at-a-glance status of applicable gas, moisture and service conditions
  • Overall summary of all monitored services equipment status
  • Web access convenience provides access from any internet-connected device and does not require software installation
  • Data display includes easy export of raw monitor data to .xls or .csv
  • Robust graphing capability, including the ability to select date ranges and data types for display.
  • Data polling standard rate – every 24 hours.


FAQ 2: What are the Technical Specifications for the G1 monitor?

Our Technical Specifications are available for download on the G1 Technical Specifications

FAQ 3: What software is needed to operate the G1 monitor and view the data?

For the G1 monitor, there is no software installation required. Monitors are set up at SDMyers’ facility and pre-configured to transmit data for availability from any web-enabled device via Transformer Dashboard.

FAQ 4: What are the advantages of doing multiple gases versus a single gas like Hydrogen?

Multiple gas monitoring allows a measure of initial diagnosis of potential fault conditions, which may help identify specific issues like arcing or corona. Regardless, SDMyers and all monitor manufacturers advise confirmation through lab testing at a reputable lab facility.


Further, both mineral oil and paper insulation (cellulose) have carbon based molecular structures rich in hydrogen. The decomposition of oil and paper insulation (cellulose) forms a large number of byproducts, including combustible and non-combustible gases. Hydrogen is naturally present in most of those compounds. The G1TM allows for an inexpensive method to signal further investigation and an DGA Lab test.

FAQ 5: How easy is it to take normal oil samples with the G1 system connected?

G1 monitor does not impede oil sampling. There is a ball valve which allows the oil sampling technician to complete his/her work without hindrance.

FAQ 6: Does Monitor Guard w/ G1TM pose any security threat to customer systems?

Monitor Guard w/ G1TM offers a simple, secure data transmission of monitor data to SDMyers’ servers. Customers can be assured that the Monitor Guard w/ G1TM does not pose a security risk, as the communication is handled via cellular modem – which keeps all communication entirely separated from any internal networks, systems, and databases. There is no possible attack vector to internal customer networks and systems, as the monitor communicates solely via the cellular modem, transmitting encrypted data (https), to SDMyers’ secure servers. It is effectively no different from walking through a site with a cell phone in your pocket.

FAQ 7: Is Guardian Monitoring with the G1 monitor available for Load Tap Changers (LTCs)?

We do not recommend using a G1 monitor for LTCs. If an LTC is a sealed-vacuum LTC and is not Reinhausen, it may be possible to monitor. SDM’s consensus is that an H2 monitor would be a poor “check engine light” for a LTC.

FAQ 8: When do alert and alarms get sent to the customer?

No automated notifications are sent to the customer without the review of the Guardian Services team.

FAQ 9: Apart from data transmission over the cellular network, what is the communication protocol for the G1?

Data is collected from the G1 system using Modbus Ethernet protocol over a VPN (Virtual Private Network, encrypted).

Modbus Ethernet protocol is a very common industrial protocol for collecting sensor data, often used in SCADA systems or other applications requiring basic data communications. Modbus Ethernet protocol does not include any security, passwords, or encryption.

The G1 solution utilizes a specialized industrial cellular modem with built in VPN technology to provide data encryption security. VPN – in layman’s terms: VPN technology is often referred to as tunneling technology.

If you had two buildings and it was dangerous to walk around outside (like the internet) then you could dig a small tunnel to safely walk between the buildings. VPN software creates these types of tunnels. For the G1TM, we created a very small tunnel, it only allows for one type of communication (Modbus Ethernet), and we only allow it to communicate to one computer. In this way, should one ever steal our VPN modem and try to hack into SDMyers, the tunnel is very small and there is no place to go.

FAQ 10: Do monitors work with FR3? What fluids can these monitors be used with?

Unfortunately, the G1 monitor can only provide adequate data for mineral oil. Further, no monitor is currently capable to monitor natural Esters Fluids, such as FR3.

FAQ 11: Who manufactures the G1 monitor?

The G1 is manufactured by SDMyers.


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