Mix and Match CTs on the 6 Three-Phase Meter Elements
The PowerScout™ can be used with a wide variety of current transformer sizes and ratings--typically split-core and Rogowski-style CTs. Any of DENT's 333mV CTs can be "mixed and matched" on any of the 6 three-phase meter element of the PowerScout™ 18, providing a versatile multi-channel submetering solution in commercial, retail, government and industrial facilities. The CT setting for each metering element is set in advance here at the factory but can also be easily changed in the field by the user with a PC, USB-RS485 converter, and ViewPoint™ software.
CTs can be changed in the field using the ViewPoint™ software utility. There are several restrictions that apply here, so contact the factory for details.
New Rogowski Coil CTs: RoCoil™
Coinciding with the PowerScout™ introduction, there are now three new sizes of Rogowski coil CTs available. The RoCoil™ is available in 16", 24", and 36" lengths. All three are rated for 3000 Amps. The Rogowski Amplifier/Integrator circuitry is now embedded in the PowerScout™--no external electronics module is required.
The communication interface to the unit is through an RS-422/485 serial connection that uses the Modbus protocol for sending commands and retrieval data. Data updates occur every 0.5 seconds. A separate remote terminal unit (RTU), Data Logger, or Building Management and Control System is usually connected to the PowerScout™ to perform data recording and trend logging functions and to provide any human interface or display.
It is our intention to add to the type of communication protocol available to customers. Ethernet and wireless options are under consideration and development. Contact the factory for specifics.
PhaseChek™ (patent pending) is a unique feature of the PowerScout™ which greatly simplifies and, at a glance, verifies correct CT orientation during installation. PhaseChek™ is a series of three colored LEDs per meter element. It works in the following way:
If two or three of the PhaseChek™ LEDs are red, then there is a phasing connection error. If two LEDs are red and one is green, switch the positions of the two CTs that are red. That should make all three LEDs green. If all three PhaseChek™ LEDs are red, the CTs are likely connected in the correct order but are off by one position. In other words, the L1 CT is on the L2 phase, the L2 CT is on the L3 Phase and the L3 CT is on the L1 phase. Rotate the CTs until all of the LEDs are green, thus ensuring a correct metering condition.
The PowerScout™ automatically adjusts for CT orientation, greatly reducing set-up time and all but eliminating installation errors. The CTs may be placed on the wires to be monitored with the CT faces in either direction. The advantage of this feature is that the installations are much easier.
The ViewPoint™ software program is designed to let the user easily configure the PowerScout™ for the current transformers connected to it and to check readings. An RS-485 to USB adapter or RS-422/485 to serial adapter is required to connect the computer to the PowerScout™.
The PowerScout™ has a choice of data scaling options. A scale factor set to "4", for example, makes all values integers. See Table 2 in the PowerScout™ manual for the available options (or the Interpreting the PowerScout Registers - Data Scaling document).