MVE CONTROL 400
MVE CONTROL is a special device for the control of small hydropower plants (SHPP). MVE CONTROL ensures generator control and delivery to the distribution power grid.
Features:
- maximizing power of the power plant by the generator control
- minimization of losses
- complete control of small hydropower plants and other components
- energy delivery to the grid even at minimal water flow (low frequency of the generator)
- low harmonic distortion of the generated current: THDi < 3%
- reactive power control, adjustable power factor (from 0.95 capacitive to 0.95 inductive), cos ф = -1 possible
- automatic flying start of the generator
- checking the grid voltage: the presence of all phases, symmetry, undervoltage, overvoltage
- checking the generator: temperature, overcurrent, short circuit, the minimum and maximum frequency
- indication of kW, kWh
- rich communication possibilities (CAN, Profibus DP, MODBUS)
- universal and fully configurable system of inputs and outputs
- comfortable setting and monitoring of the devices via graphical control panel
Monitoring:
MVE CONTROL 400 continuously monitors and controls:- symmetry and the presence of all three phases of the supply of the grid (in case of problem, it disconnects the MAIN AC CONTACTOR
- water level
- instantaneous power in kW
- summary of the energy delivered to the grid in kWh (for information)
- regenerative or motoric operation of the water wheel/turbine (motoric mode immediately switches off the operation - except start-up of the power plant) - this feature can be turned off
- temperature of the generator
- temperature of the device
Technical data
| Input part | |
|---|---|
| Grid voltage Vs: | 3 x 400 V AC ± 10% |
| Input voltage frequency: | 50 Hz ± 5% |
| Current THD: | < 3% (at voltage THD < 1,5%) |
| Nominal power: | 4 - 500 kVA |
| Rate of the shutdown by the loss of voltage in a supply phase: | < 10 ms |
| Generator part | |
| Supply voltage of the generator: | 3 x 0 to Vs |
| Frequency of the generator: | 0 - 60 Hz (according to the output of power maximization block) |
| Nominal power of the generator: | 4 - 500 kW |
Degree of protection:
| Protection of electronic part of the enclosure: | IP 55 |
|---|---|
| Protection of the ventilated part of the enclosure: | IP 21 |
Equipment of the enclosure:
- Power electronics
- Input contactor
- Input fuses with the fuse switch disconnector
- Inpput overvoltage protection
- Transformer for the control voltage
- LED pilot lights (napr. RUN, FAULT, VOLTAGE PRESENT, VALVE OPEN)
- Auxiliary relays
- Time relays
- Circuit breakers
- Tempering of the enclosure
- Ventilation of enclosure - the power section
- Contactor of valve magnet
- Service socket 230 V
- Input and output terminals
- Grommets
- Rotary switch START
Description of the operation of wheel motors with SHPP:
Start:
When the START switch is turned to the ON position, the main input contactor is closed.
In series with the START switch contact of water level sensor that blocks INPUT switch contactor at low water,
respectively. off the main contactor in the absence of water. Then, however, remains on the START switch is in the ON position, the system is therefore
automatically after switching level sensor. After switching - clipped by the network can handle up to about 3 times the
(must run the initialization of power electronics systems). For a specified period of current drawn from the mains only about 5%
nominal current (DC controlled charging circuit) and during that time the system does not operate a network controlled inverter.
Turning of:
Switching the START selector to OFF de-energises the main INPUT CONTACTOR of the switchboard. A latching STOP push-button
is wired in series with the contactor coil, so pressing STOP also drops the INPUT CONTACTOR and disconnects the unit from
the grid. The STOP push-button is mounted on the switchboard, and additional STOP buttons can be wired around the SHPP.
Where unauthorised use of the STOP button is a concern, or where the switchboard's location inside the SHPP makes the
button unnecessary, it may be omitted from the circuit.
Flying start:
After the INPUT CONTACTOR is energised the unit is ready for operation. If the water-wheel motor is already spinning under
external drive, the control electronics determine its speed without a speed sensor and set the output frequency exactly to
the generator frequency - a flying-start synchronisation with the generator. Once synchronised, the power-maximising
algorithm sets the most favourable supply-voltage frequency for the generator.
Maximizing the power of SHPP:
MVE CONTROL 400 includes a dedicated software feature (SHPP power maximisation) that automatically tracks the maximum
available generator power by optimising both the generator speed and the voltage at the current operating point. This
feature is optional and can be left disabled.
Shutdown at the low water level:
Shutdown at minimum water level is implemented by dropping the INPUT CONTACTOR. While running (input contactor closed),
MVE CONTROL 400 continuously monitors the generator; if the minimum flow no longer allows generator-mode operation, the
unit automatically transitions into STAND BY.
Protections:
Grid-side input protection: an overvoltage protection device is wired at the switchboard input, and the power electronics
are protected by fast gR-class semiconductor fuses.
Generator protection: current, power and temperature of the generator are continuously monitored by both the hardware and
software of MVE CONTROL 400.
Shutdown at the failure:
On a system fault (for example a power-electronics failure) the power output of MVE CONTROL 400 is naturally blocked, and
the unit attempts a restart after a configured delay. If the underlying cause has cleared (for example generator overload
or a grid overvoltage), MVE CONTROL 400 resumes normal operation. During a fault the water-inlet solenoid valve is also
closed. After the fault clears, or once supply voltage returns following an interruption, the water-inlet solenoid is
re-opened via a time relay set to roughly 5 s. This delay is needed because the power electronics need about 3 s
after re-connection to the grid to complete control-system initialisation; only after initialisation has finished may
water be admitted to the water-wheel motor, at which point the automatic flying-start synchronisation can engage on the
spun-up wheel.
Shutdown in case of failure of one supply phase:
MVE CONTROL 400 continuously monitors the presence of all three phases of the mains voltage at its input. During power phase loss, it immediately (within 10 ms) blocks the operation of power electronics,
and MVE CONTROL 400 stops supplying power to the grid. If the loss has ended, MVE CONTROL 400 is put back into operation automatically.
Activity at limit temperatures:
The enclosure is ventilated for heat dissipation and also equipped by ventilation at temperatures below + 5 ° C.
Low temperatures:
When the temperature during turn on of the device is below + 5 ° C, condensation of water on the electronics may occur. Therefore, the enclosure is first "heated up" to a temperature of +5 ° C
and then the input contactor is switched. Therefore, the heating is connected before the input contactor .
High ambient temperatures:
MVE CONTROL 400 constantly monitors the temperature of its cooler and power elements. It is designed for operation up to the ambient temperature +40 °C.
At higher ambient temperature, it is necessary to reduce the power by about 1% per 1 °C. When overheated, MVE CONTROL 400 is automatically turned off.
Type of the generator:
As the generator standard induction motor can be used. Due to possible overheating check at maximum power we recommend motor with built-in temperature sensors in the windings.
MVE CONTROL 400 checks the temperature of the motor and blocks its operation when overheated.