Video: GRIDSCAN 5000 – Installation

Video transcript

From Amperis: how the GRIDSCAN 5000 is installed, wired, configured, and what happens inside it. First, the rules. Installation and maintenance must be carried out by certified installers authorised to work on the transformer. Switch off electrical power before making any connection, and make the ground connection first. What the job needs: a wrench, a suitable 4 conductor cable, thread sealant, a 3 quarter inch valve, and a 10 watt industrial power supply.

Where it goes. As close to the tank as possible, on a valve of 3 quarters of an inch or larger, with any pipework of at least one inch inside diameter, and away from turbulent oil flow. Orientation matters. In oil the monitor mounts horizontally, so that no air bubble can form around the sensing element. Angles from 180 to 360 degrees are acceptable; one to 179 degrees is not. In the gas space, horizontal or vertical are both fine. The mechanical connection.

Keep the red cap on until the last moment, seal the threads, and put the wrench on the housing closest to the thread. Standard torque for a 3 quarter inch NPT fitting is about 50 pound feet. Do not over tighten. On an oil calibrated unit, the trapped air has to come out. Close everything, open the bleed, crack the transformer valve until oil runs without bubbles, close the bleed, then open the valve fully and check for leaks. The electrical side is one cable.

Four conductors carry DC power and two wire RS-485 to the customer equipment, with the cable shield earthed at one end only. The pin out of the M 12 connector: pin one, DC power, brown. Pin two, DC ground, white. Pin 3, RS-485 data plus, blue. Pin 4, data minus, black. Power and bus. An industrial, substation rated supply of 12 to 48 volts DC, 10 watts. The RS-485 input is galvanically isolated, and a 120 ohm termination resistor is already fitted inside the monitor.

Power it up, and be patient. The monitor runs a self test, restores its settings, starts measuring, and calibrates itself. On a new installation that sequence can take up to 16 hours before the readings are accurate. Inside, it is simpler than a chromatograph and that is the point. At the tip, the solid state palladium alloy sensing element. Behind it, a hermetic glass to metal feedthrough and gaskets form a gas tight barrier.

Then the 5th generation electronics, with an isolated regulator and a galvanically isolated bus, and a supercapacitor that keeps the clock alive. In service it runs its own routine. Oil temperature about once an hour for temperature compensated readings, and every 10 hours or so a reference cycle of around two hours, during which the monitor holds its last hydrogen value. No user action is required. The ScanH two utility does the commissioning. It connects over RS-485 or through an Ethernet bridge,

sets the protocol and address, synchronises the clock, selects the insulating liquid, and reads or writes the whole configuration file. And what to poll. Registers 0 and 1 for hydrogen, and the high word must be read first. Register 8 for oil temperature. Register 111 for status, and 112 and 13 for errors. GRIDSCAN 5000, from Amperis.