HT (High Tension) and LT (Low Tension) panels: These definitions differ, HT and LT are common terms used in the electrical systems process but it is a must to distinguish both these panel types when you start working on any kind of electric applications. As on standing in front of two panels, one to the right side is HT panel and other is left side LT panel. How they help you as a HT here we listed some few points.
- Panel Construction and Design
Right Side Panel(HT panel)This is drive dedicated panel construction. Each drive has its own dedicated feeder, so clearly we were losing top to bottom. You have the relay section and then isolator followed by indication circuit to watch the current. Lower — vacuum contactor and fuse. The layout is that a row shows only one drive, and there are multiple series of other operations relating to this drive.
Left Panel (LT Panel): On the opposite side, each rows of drives can take multiple. An example: a row providing power to two or more drives. Smaller than the right panel, with multiple rows of feeders that are feeding power to different drives.
- Voltage Levels
HT Panel as the name suggest high tension voltage i.e. any no less than 1000 volts (1 kV). When you do the above things, if that right side panel is an HT panel or not check on incoming section voltmeter. So, in this example: if it reads 6.6 kV that is our answer and we know the panel belongs to HT Panel
Low tension panel (above 1000 volts) If voltage meter of left side panel shows 400 volt, then it is an LT Panel. Panel classified as LT, if volt meter reading is 700 volts ( even it shows a voltage close to the limit of higher rating )( example : voltmeter showms697 volts) Panel will be considered as Low Tension one.
- Rear Side Configuration
HT Panel: On the backside of the HT panel, each row corresponds to the front layout, where one row is dedicated to one drive. The motor cable terminations, along with current transformers (CT), are located here for measuring current flow.
LT Panel: The back of the LT panel is different because it contains breakers which need more space for cable termination. You can see how the panel sticks out a tad in locations where there are breakers installed, since they need extra space.
- Identifying HT and LT Panels
Look Voltmeter: The simplest way of ascertaining the panel type is by checking on the voltmeter in incoming section. If the voltage is more than 1000 volts, then it will be HT panel and if below 1000volts then LT panel.
Look at the Panel Design: Normally HT panels have one row for each drive whereas LT panel can accommodate multiple drives from single row
Backside View : HT panel for motor cable terminations and CTs, LT Panel is with breakers, may slightly be project towards back due to cable spacing requirements.
These HT and LT panels can be easily distinguished based on construction, voltage levels, back panel configuration etc.
By following this guide, and with the help of expert LT panel manufacturers in Kolkata, you can confidently identify and work with both HT and LT panels in your electrical projects.
