ABB MEGADRIVE LCI medium voltage load commutation inverter

Product Overview

MEGADRIVE LCI has been on the market since 1974 and has over 40 years of engineering application experience. It belongs to high-power thyristor type medium voltage transmission. Two major working modes:

LCI.DR speed regulation mode: synchronous motor continuous variable frequency speed regulation;

Soft start mode LCI.SO: Smooth accelerate a large synchronous motor from 0 to rated speed, and then connect it to the grid and switch to the power frequency grid for operation; A single device can sequentially start multiple motors of different powers;

Gas turbine start-up LCI.ST: drives the generator to act as an electric motor, raising the speed to the ignition speed of the gas turbine to complete the start-up of the gas turbine.

Applicable industries: oil and gas chemical industry, water supply (large pumps), metallurgy (blast furnace fans, wire mills), power generation (gas turbine start-up, pumped storage, boiler feedwater pumps); There are also special working conditions such as test benches and wind tunnels.

Core values and product advantages

1) Energy efficiency and reliability

The overall efficiency of the inverter is greater than 99% (including DC reactor losses); Adjust speed according to process requirements, save electricity, and reduce CO ₂ emissions.

Design without fuses: Thyristors have strong surge resistance, blocking triggering pulses and tripping the main circuit breaker in case of faults, reducing spare parts and improving availability; Thyristors can be connected in series to achieve N+1 redundancy, further improving system fault tolerance.

Rectification supports 6-pulse/12-pulse/24-pulse configurations, and harmonics meet IEEE 519, IEC, and GB/T 14549-93 standards to reduce harmonic interference to the power grid.

2) Highlights of Control Technology

MPTC model predictive torque control: maintains partial torque output under grid disturbance conditions, has voltage drop ride through capability, and resists short-term main circuit and auxiliary power outage disturbances; Support power factor optimization and advanced process protection.

Encoder free operation: No need for motor shaft end speed/position encoder, reducing on-site sensor failure points and improving system availability.

Energy feedback capability: The motor can operate under generator conditions, and the power is sent back to the grid in reverse to achieve motor braking without the need for additional power devices.

Low speed manual commutation: 0-10% of rated speed, insufficient motor back electromotive force, manual commutation is enabled to ensure reliable operation of the inverter.

Excitation converter: compatible with brushless excitation and slip ring excitation synchronous motors; The full speed range includes providing excitation current at zero speed.

3) Security features

Anti arc cabinet (IAC) option, protects personnel and equipment, reduces arc fault shutdown;

SIL/PL certification for functional safety;

LCT touch screen local operation terminal, graphical and digital display of operating status; Integrated emergency stop button.

4) Maintenance and Service

The components are easy to inspect and maintain; The water-cooled model is equipped with a maintenance free pump; Support ABB Ability remote status monitoring;

Support complete turnkey package solutions: including medium voltage converters, matching motors, and converter transformers; ABB has completed joint testing, with a single interface responsible for quotation, delivery, and full lifecycle services.

Key points of system integration design

Designing a complete transmission system requires a comprehensive evaluation of four dimensions:

Mechanical interface: torque pulsation, shaft torsional vibration; It is necessary to conduct torsional vibration analysis to evaluate the safety of the shaft system (corresponding to the transmission chain vibration damping option in the previous document).

Power supply interface: The inverter can withstand grid disturbances, suppress harmonics generated by the inverter, and meet power quality standards.

Automation and operation interface: Hardwired analog/switch signals, or serial communication bus, connected to the factory level DCS control room.

Environmental conditions: equipment size and weight, cooling method, protection level EMC、 Noise, altitude, and ambient temperature.

Complete solution: Integrated delivery of inverter+motor+converter transformer; The converter transformer achieves electrical isolation between the power grid and the transmission system, and adapts to the voltage level of the power grid.

Two major hardware versions: air-cooled and water-cooled

The air-cooled MEGADRIVE LCI is commonly used in low to medium power scenarios; Install cooling fans on the top of the cabinet; Standard IP30, optional IP31, IP41; The maximum noise level is 85 dB (A).

Water cooled MEGADRIVE LCI (LCI. W, corresponding to the hardware manual previously read) high-power main model; The water-cooled unit takes away most of the losses, and the heat load inside the cabinet is low; Suitable for dusty and corrosive environments; Standard IP30, optional IP31/IP41/IP54; Noise ≤ 75   dB (A).

Cabinet composition: Converter power cabinet (rectifier, inverter thyristor stack), DC reactor cabinet, terminal unit, water-cooled unit (water-cooled model), control unit (LCT+AC   800PEC controller).

Key technical parameters

Category parameters

Input rectification 6-/12-/24 pulse thyristor rectification

The input voltage relies on the input transformer to adapt to any voltage level

Voltage fluctuation ± 10% without derating; +20%/-50% deratable operation, MPTC achieves deeper drop crossing

Input frequency 50/60 Hz, allowable deviation of ± 5%

Power factor rated condition is approximately 0.85 inductive

Output power ranging from 2 MW to 150 MW (higher power can be customized)

Output voltage 2-10 kV (up to 2 × 25 kV)

Output frequency 0-120 Hz

Suitable for synchronous motors (slip ring/brushless excitation)

Inverter efficiency>99%

Protection level standard IP30; Optional air cooling IP31/41; Water cooling options available IP31/41/54

Altitude ≤ 1000   m; above 1000   m, derating is required

Environmental temperature+5…+40 ℃; Overtemperature derating

Cooling medium temperature (water-cooled)+2~+32   ℃, exceeding it requires derating

Noise water cooling ≤ 75   dB (A); Air cooling ≤ 85 dB (A)

Standard EN, IEC, CE; CSA optional

The sample provides a detailed selection table, divided into three categories:

LCI (water-cooled 12/12 pulse) for speed regulation: including regular version and N+1 thyristor redundant version; Including power, model code kVA、 Cabinet length and overall weight.

Soft starter LCI (air-cooled: 6/6-pulse, 12/12-pulse, 12/6-pulse), models, capacities, external dimensions, and weights of different power levels.

Selection parameters for LCI (air-cooled 6/6-pulse, 12/6-pulse) for gas turbine start-up.

The sample data is used as a reference value, and the final project is based on the project drawings (Appendix A/B).

ABB’s full lifecycle service system

ABB Motion Services Service Module

OneCare Modular Service Agreement;

Plan maintenance, fault repair and recovery;

Digital innovation, data and consulting services (torsional vibration analysis, implementation of vibration damping functions);

Upgrading and performance improvement; Energy efficiency and circular economy; Full lifecycle management.

ABB Ability ™ Real time KPI, alarm, and equipment health assessment of the transmission chain (driver+motor) through portal website for transmission status monitoring; The standard package includes self monitoring, alarm management, asset health, technical support, and backup management; Optional value-added services such as offline data collection, expert reports, and remote assistance; Anticipate faults in advance and reduce unplanned downtime.

Four stages of product lifecycle

Active period: normal production and supply, full set of services;

Classic period: Stop mass production, provide spare parts, upgrade and upgrade;

Limited Support Period: Spare parts are only in stock and support is limited;

Obsolvete elimination period: only providing replacement and scrapping related services. ABB will release a lifecycle announcement to allow users to plan spare parts and modifications in advance.