Feeder and Motor Manager Block V255

Features and technical specifications:

1. Fully digital signal handling with a powerful 16-bit microprocessor, and high measuring accuracy on all the setting ranges due to an
   accurate 16-bit A/D conversion technique.
2. Wide setting ranges for the protection functions, e.g. the earth fault protection can reach a sensitivity of 0.5%.
3. Integrated fault location for short-circuit faults.
4. The device can be matched to the requirements of the application by disabling the functions that are not needed.
5. Flexible control and blocking possibilities due to digital signal control inputs (DI) and outputs (DO).
6. Easy adaptability of the device to various substations and alarm systems due to flexible signal-grouping matrix in the device.
7. Possibility to control six objects (e.g. circuit-breakers, disconnectors).
8. Status of eight objects (e.g. circuit-breakers, disconnectors, switches).
9. Freely configurable display with six measurement values.
10. Freely configurable interlocking schemes with basic logic functions.
11. Recording of events and fault values into an event register from which the data can be read via a keypad and a local HMI or by
    means of a PC based VAMPSET user interface.
12. Latest events and indications are in non-volatile memory.
13. Easy configuration, parameterisation and reading of information via local HMI, or with a VAMPSET user interface.
14. Easy connection to power plant automation system due to a versatile serial connection and several available communication
    protocols.
15. Built-in, self-regulating ac/dc converter for auxiliary power supply from any source within the range from 40 to 265 Vdc or Vac. The
    alternative power supply is for 18 to 36 Vdc.
16. Built-in disturbance recorder for evaluating all the analogue and digital signals.
17. Eight (8) programmable stages for alarming or protection purposes

This Feeder and Motor Manager Block is easily insert in your schematic diagram and connect as you like way.

The device is fully designed using numerical technology. This means that all the signal filtering, protection and control functions are
implemented through digital processing. The numerical technique used in the device is primarily based on an adapted Fast Fourier Transformation (FFT). In FFT the number of calculations (multiplications and additions), which are required to filter out the measuring quantities, remains reasonable. By using synchronized sampling of the measured signal (voltage or current) and a sample rate according to the 2n series, the FFT technique leads to a solution, which can be realized with just a 16 bit micro controller, without using a separate DSP (Digital Signal Processor). The synchronized sampling means an even number of 2n samples per period (e.g. 32 samples per a period). This means that the frequency must be measured and the number of the samples per period must be controlled accordingly so that the number of the samples per period remains constant if the frequency changes. Therefore secondary testing of a brand new device should be started
with voltage protection functions and voltage injection to let the relay learn the local frequency. However, if this is not possible then the
frequency must be parameterised to the device. Apart from the FFT calculations, some protection functions also require the symmetrical components to be calculated for obtaining the positive, negative and zero phase sequence components of the measured quantity. For example, the function of the unbalanced load protection stage is based on. The device enables capacitor, filter and reactor bank protection, with its five current measurement inputs. The fifth input is typically useful for unbalance current measurement of a double-wye connected
unearthed bank. Furthermore, the unbalance protection is highly sensitive to internal faults of a bank because of the sophisticated natural unbalance compensation. However, the location method gives the protection a new dimension and enables easy maintenance monitoring for a bank. This protection scheme is specially used in double wye connected capacitor banks. The unbalance current is measured with a dedicated current transformer (could be like 5A/5A) between two starpoints of the bank. The unbalance current is not affected by system unbalance load. However, due to manufacturing tolerances, some amount of natural unbalance current exists between the starpoints. This natural unbalance current affects the settings, thus, the setting has to be increased.