Video: APD-ANNUNCIATOR – Technical guide

Video transcript

How the APD-ANNUNCIATOR is fitted on switchgear in service, how the sensors and modules are wired in cascade, how the alarm thresholds are set, and how the system is checked. The cabinets stay energized while the system is fitted, so the work follows the site's safety rules and is done by authorized staff. External sensors go on the outside of the enclosure without opening it. Anything that goes inside a cabinet or onto an earth conductor is fitted only under the site's procedure for that compartment.

To site go the modules, one per cabinet or group of sensors, up to three sensors for each module with their coaxial cables. Standard RJ45 cables for the chain, a 9 to 24 volt DC supply, and the dust boot kit for dusty or outdoor locations. Every connection is at the two ends of the module. One end has an I.O. port and sensor inputs 1 and 2. The other has the USB configuration port, a second I.O. port and sensor input 3. Both I.O.

ports carry Modbus and the DC supply, in and out. Each sensor goes where the discharge would show. The contact version sits flat on a clean metal panel, close to the cable box or the bus bar. The airborne version faces a vent or a gap where ultrasound escapes. The internal version is fitted inside, near the cable terminations. The high-frequency clamp goes around the earth conductor of the cable, where discharge pulses the discharge pulses return to ground.

It opens on its spring latch closes around the conductor, and its coaxial cable goes to a free sensor input. The 20 mm clamp fits braids and small conductors. The 60 mm one, larger ones. One module, wired. The three sensors go to sensor inputs 1, 2, and 3. The RJ45 cable from the previous module, or from the supply, goes into one I.O. port, and the other other I.O.

port continues to the next module. The USB port is only used to configure it from a PC. A row of cabinets is wired in the same pattern. First, the sensors of every cabinet to their module. Then the RJ45 cables from module to module. The 9 to 24 volt supply goes in at one end of the chain, and the Modbus link to the SCADA leaves from the other. Commissioning follows one order.

Fix the modules and the sensors. Connect the sensor cables. Chain the modules with RJ45. Only then switch on the supply, and check the green lamp on every module. Configure from a PC, and finally connect the SCADA. Each acoustic and HF channel gets its own threshold. Watch the channel for a while first, to see the normal background of the site. Then place the threshold above it.

The interface can raise it automatically 6 dB over the present level, and each channel's alarm is enabled separately. the SCADA, the system is a Modbus RTU device. The SCADA reads the levels and alarms of every channel, stores the samples, and draws the trends, and it can also push new settings back to the modules. a channel crosses its threshold, for things happen at once. Its lamp lights on the module. The dedicated hardware output switches for a local alarm or a relay.

The status goes to the SCADA. And with the remote access solution, the SMS and the email go out. Before leaving site, prove the chain end-to-end. The portable partial discharge simulator runs on batteries and checks the integrity and response of the installed sensors. The channel lamp must light, and the alarm must reach the SCADA. The same test is repeated at each maintenance visit. An alarm is the start of a diagnosis, not the end.

Look at the trend. Rising, steady, or tied to load or humidity. Compare the HF and the acoustic channels of the same spot. Then send a portable survey to locate the source and plan the repair before it fails. Maintenance is light. Keep the dust boots on in dusty or outdoor locations. Keep sensor faces clean and seated flat. Check that cables are secure after any work in the cabinet. And retrieve the stored data through USB whenever the remote link is not available.

Partial discharge detection from Amperis.