Voltage Threshold Simulator

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Have you ever been uncertain what threshold voltage to choose when selecting a DC decoupler? Or maybe you are observing unexpected potentials across a protected isolator? If a decoupler is applied with an incorrect threshold voltage rating for the application, it may not provide the intended isolation of galvanic potentials.

Selection of the proper decoupler voltage threshold rating depends on several system parameters: Pipeline and grounding potentials, AC current flow, power frequency, and the AC impedance of the decoupling device. Dairyland’s decoupler voltage simulator makes this selection process easier by allowing you to predict the closed-circuit voltage across a properly installed Dairyland decoupler. Based on the provided system information, the simulator outputs the open-circuit DC and total voltages across the device and also displays the expected closed-circuit DC and total voltages across the installed device vs. time. The simulator will also indicate when the device is expected to be in conduction – i.e., passing both AC and DC.

In the fields provided, enter the intended Dairyland device and voltage threshold rating.  Then enter the open-circuit DC potentials (Vp/s ref. to Cu-CuSO4) of connections to both the negative and positive device terminals. For example, for an AC mitigation installation, the negative decoupler terminal would have an open-circuit DC potential equal to the pipeline potential at that location and the positive terminal would have a potential similar to the galvanic potential of the grounding material (i.e., approx. -1.0V ref. Cu-CuSO4 for Zinc). Then specify the amount and frequency of any steady state AC current expected to flow through the device. This current can be an estimate from models or measured directly on an existing system using a clamp-on ammeter. When selecting a new decoupler, be sure to use the maximum AC current that is expected over time, taking into account known or estimated load cycles.

By experimenting with various devices, voltage threshold ratings and system parameters, you can use this simulator to ensure your selection of device and voltage threshold rating do not cause the device to go into conduction during normal operating conditions.  If you have any questions along the way, contact techsupport@dairyland.com.