RNHV series smart medium voltage variable frequency drive (AC drive or frequency inverter), adopting power cell series connection technology, directly outputs 6 and 10kV voltage. It is a high voltage-high voltage VSI (Voltage Source Input) VFD. Renle regards high reliability, simplified operation and high performance as its design goal so as to meet the urgent requirements of the users for mechanical speed control and energy saving of fan and pumps and improvement of production technologies etc. In order to shorten the construction period required for installation and reconstruction of MV VFD system, Renle introduces the integrated design for the drive, which consists of all components and inner wiring of transformer cabinet, power cabinet, control cabinet and MV switchgear (bypass cabinet is optional). The user is only required to connect MV input/output cables, LV control power supply and control signal cables etc. The complete drive has been wholly tested prior to delivery so that both quality and performance of every product is guaranteed.
In order to meet the requirement of transformation project and reduce the investment of new project, every function part of RNHV series frequency inverter can be installed step by step. In this way, it is ensured that there is no accident during transportation and installation. Convenient front-back maintenance, high-performance key imported components, and advanced production technologies, all these greatly reduce the requirements of the drive for the site environment.
Working principle and diagram：
Each phase of the RNHV medium voltage drive consists of power units in series connection with the function of voltage boost through superposed wave. Every power unit is provided with independent phase-shift power by the isolation transformer. By the means of changing the quantity of series units, it is convenient to obtain output of different voltage levels. The power unit adopts AC-DC-AC method. IGBT is used as the main circuit switching element.
Working Principle Diagram of 6/10kV MV
1）Adapted to rigid environment
● Smooth operation at ambient temperature -5 to 40°C without capacity reduction (derating);
● Excellent heat dissipation design, advanced S-shape air duct, long-life, large airflow cabinet-roof fans, and air intake filters that feature low wind resistance, strong dust-proof capability and easy disassembly;
● Superior power network adaptability that enables the drive to work without stop under +15~-25% of rated voltage;
● Coated circuit board that resists rigid environment;
● With super large margin design the power units can be designed and operated under 120% of load. All electronic components are designed and evaluated with 90% derating according to national standards.
● The product offers three kinds of control modes: V/F, vector control with PG, vector control without PG;
● Multifunctional self-adaptive V/F feature ensures maximum start torque;
● DSP + Field Orientation Control (FOC) technology ensures optimum dynamic features;
● CAN bus communication torque distribution control is applicable to mulitmachine reconnection;
● Precise inverter nonlinear compensation acquires good low speed features;
● Neutral point drifting technology ensures maximum output power and reduction of power during bypass running of the power cells;
● Power cell automatic bypass technology;
● Perfect fault self-diagnosis and self-repairing ability; Power grid gapless synchronous switching;
3）Adapted to rigid environment
● Perfect input at the grid side without harmonics. Harmonics control and suppression device not required;
● Efficiency of the complete VFD is above 96%;
● HV-HV structure directly outputs 6kV or 10kV voltage. No request is needed to modify the motors; Forward/reverse rotation speed tracking and restart
● function is particularly applicable to such load as fans.
4）High quality after-sales service
● RENLE offers rapid one-stop service to customers during the service life of the equipment;
● Suggestion and tracking from specification establishment to aftersales services;
● RENLE’s service network is all over China.
Power supply: 3-phase, 6/10kV, 50/60Hz
Input voltage range: Voltage: -15%~ +10%; Frequency: 2%
Rated voltage: 3-phase, 6/10kV, 50/60Hz
Frequency range: 0～120HZ
Set resolution: 0.01 HZ
Overcurrent capacity: 120% of rated output current for 1 minute; protection starts immediately under 180% of rated output current
Control mode: V/F, vector control with PG, vector control without PG
Synchronous switching: The VFD attains the status of grid-connected operation by following the phase and frequency of the voltage, so it realizes smooth switching from frequency conversion to working frequency without impact.
Torque compensation: During start stage torque boost is realized automatically up to 150% and above
Slip compensation: To compensate the speed drop under load and increase the hardness of mechanical characteristics
Upper and lower limits of frequency: Setting of upper and lower frequency limits is available
Jump frequency: Setting of three groups of jump frequencies is available
Rotation speed tracking and restart: Switching to frequency conversion mode for operation without stopping the running motor
Acceleration and deceleration time: 0.1~3600 sec. Independent setting of acceleration and deceleration time is available
Acceleration and deceleration integral type: Linear, S1 and S2 curves are selectable to meet different application requirements
Operation mode: Operation on the VFD, local operation, remote operation
Stop mode: Free stop, deceleration stop and deceleration plus DC braking stop are selectablePID closed-loop control: Applicable to different closed-loop control systems of flow, pressure and temperature etc.
Neutral point drifting: Any power cell can be bypassed. Through neutral point drifting technology, the 3-phase output is still balanced. In this way, maximizationof VFD’s output power is ensured after one power cell is bypassed. So when a certain power cell has fault, it can be bypass and the normal operation is not influenced.
Automatic power cell bypass: When a certain power cell has fault, the VFD will automatically bypass the faulted power cell and continue running through the Neutral Point Drifting technology. Without manual intervention. When two or more power cells are bypassed, the user can perform derated running according to requirements.
Restart-after- power failure: When power grid fails abruptly, the VFD can be restarted within the set time after the power is resumed. The VFD will go back to its status before power failure without manual intervention.
Frequency setting: nalog input signal setting: setting is realized with 0~10VDC voltage signal, 0~20MA, 4~20MA current signal.
Multi-frequency selection setting: selection of 1~7 frequency operation is available by combination of digital quantity input ports
Field bus: Modbus,TCP/IP, PROFIBUS-DP Operation state output signal: Relay output: selectable to display running states of operation, stop and fault etc.
Analog output: selectable to display frequency, current, voltage, rotation speed or other running parameters.
During running/stop state: To display frequency, current, voltage and power
During setting state: To display set menu number or set parameters
During function operation state: To display prompting information of function being operated
During alarm and fault state: To display different alarm and fault codes
Overload protection: To monitor output current of the drive to protect it when overload occurs
Overvoltage protection: To monitor overvoltage at DV bus and input voltage of the drive for protection of the drive
Surge voltage protectionL: This function protects the drive on the occasion of surge voltage among side lines of input power supply or between the lines and the earth
Undervoltage protection: To monitor input voltage to protect the drive when undervoltage occurs
Overheating protection: To monitor the temperature rise of the heat radiator for protection of the drive when the rise exceeds the set valueShort circuit protection: This function protects the drive when short circuit or overcurrent occurs at the output side of the drive
Overload protection of electric motor: To monitor the overload running of the motor for protection of it
Phase failure protection: To monitor input voltage failure for protection of the drive
Application place: Indoors application with altitude below 1000m above the sea level; Without erosive gas and flammable gas; no dust, mist or water drop etc; No direct exposure to sunshine and no interference of strong magnetic field. The drive has to be derated at altitude over 1000m
Temperature of application: -5℃～+40℃
Humidity of application: 5～95%RH((with no frost)
Storage temperature: -40℃～+70℃
Protection level: IP30
○ Thermal power plant: Such as fan, compressor, p u m p e d s to r a g e p u m p , induced draft fan, condensate pump, circulating water pump and boiler feed pump etc.
○ Petroleum, petrochemistry and natural gas: Such as pipeline transportation pump, water injection pump, water feed pump, submersible pump, circulating water pump, brine pump, compressor, pressure blower, oil transfer pump and electric submersible pump etc.
○ Coal industry and mines: Such as scale removing pump, mud pump, slurry pump, clean water pump, feeding pump, axial flow fan, stirring pump, kiln, belt conveyer, dedusting fan, drainage pump, medium pump and counter-rotating fan etc.
○ Steel industry and nonferrous metallurgy: Such as blast furnace blower, induced draft fan, compressing blower, draft blower, water feed pump, water supply pump, dephosphorization pump, dedusting fan, converter and blast furnace etc.
○ Cement and construction material: Such as blast furnace blower, induced draft fan, compressing blower, draft blower, water feed pump, water supply pump, dephosphorization pump, dedusting fan, converter and blast furnace etc.
○ Municipal construction: Such as (for heating, water supply and waste water treatment etc.) aeration blower, induced draft fan, draft blower, pressure pump, hot water circulating pump, sewage pump, water purifying pump, lift pump, water supply pump and reclaimed water pump etc.
○ Light industry and chemical industry: Such as gas blower, pressure pump, compressor, axial flow
pump, water softening pump and water supply pump etc.
Product outer dimensions and parameters
Transformer cabinet, Schematic diagram of control cabinet appearance
10KV high voltage inverter configuration table