ABB ACS1000 high voltage inverter in petrochemical plant the application of rich gas compressor

First, introduction

With the ACS1000 gas compressor application ABB development ACS1000 gas compressor application ABB of power electronics technology and converter technology, high voltage large capacity variable frequency speed regulation technology both at home and abroad to get a rapid development and extensive application of, especially high voltage frequency conversion is used to drag power equipment such as fan and pump season can effect is remarkable, considerable economic benefit. Petrochemical plant coking rich gas compressor workshop residue catalytic cracking unit is the unit of key equipment, because of technological requirements need speed, the traditional way of speed control using turbine machine, covers an area of large, low efficiency, with the development of the high voltage large capacity variable frequency speed regulation technology, high voltage frequency converter has been widely used. Coking rich gas in the process of compressor operation, the change of molecular weight, and high compressor rotate speed, the highest speeds above 12000 RPM, the frequency converter, high dynamic performance requirement for wuhan petrochemical, coking rich gas compressor workshop residue catalytic cracking unit, we the comprehensive examination, given the current usage of the most advanced high voltage frequency converter has been put into operation, cost performance, adaptability, dynamic response speed, volume, cooling way, input and output waveform situation, the index factors such as noise, finally in this project chose ABB ACS1000 series 12 pulse water cooled type high voltage inverter direct torque control system.

Second, the main characteristics of ACS1000

World electrical giant ABB ACS1000 series high-voltage converter is a high - high direct type high voltage inverter, the power of 315 kw, 5000 kw, the output voltage level is 2.3, 3.3, 4.16 KV, when pick up 6 KV voltage class motor, the motor must be changed to delta connection. Inverter, the capacity of 3.3 KV voltage class in 2150 kva and below the inverter adopts air cooling, with capacity above 2150 kva and inverter adopts water cooling.

ACS1000 high voltage frequency converter for motor and cable has no special requirements, also need not motor capacity use, apply to domestic motor completely; ACS1000 high-pressure transducer less component, compact structure, small volume, simple system integration; ACS1000 adopted power device IGCT (Integrated Gate Commutated Thyristor converter Thyristor) Integrated door, IGCT is rapid, balanced in flow, low loss, ACS1000 type is a voltage source inverter, directly using IGCT high voltage power device, compared with other the topology structure of the frequency converter, greatly reduced the number of power device, main circuit principle diagram as shown in figure a, simpler structure, higher efficiency and reliability is much higher.

ACS1000 dc circuits adopt IGCT instead of fuse as the protection of the inverter main circuit, IGCT breaking time is 25 mu s, 1000 times faster than the traditional fuse, greatly improving the shut off speed, so as to improve the reliability of protection. IGCT also has the following advantages:

(1) the fly-wheel diode integrated on the same chip

(2) does not need to buffer circuit

(3) control circuit and power device integrated into an organic whole

(4) high reliability (element) less total

5. High power density (total number of components and low loss less)

ACS1000 adopts the technology of the direct torque control (DTC), do not need to install pulse in the motor shaft encoder and provide accurate speed and torque control, DTC can output full torque at zero speed. In DTC, the stator flux and torque as the main control variable, with a high speed digital signal processor, the motor is running the actual value and reference value to compare, implementation for each of the inverter switch state determined separately, so remain the best combination switch gear, mutation or the power to load disturbance caused by the dynamic changes of a rapid response.

Third, the system structure and characteristics

1, into the line power frequency high voltage as a frequency conversion circuit fault state to ensure that the motor and the compressor running backup guarantee, under normal circumstances by frequency conversion into line ark to inverter power supply, frequency converter into the line of high voltage must be controlled by frequency converter the closing.

2 and 12 pulse isolation transformer by domestic production, transformer has two secondary windings, a Y connection, a method for Δ, two winding with alternate with 30. The phase difference. Adopts 12 pulse isolation transformer ACS1000 transducer has met the IEEE519-1992 and the UK g. 5/3 when the demand for harmonic voltage and current.

3, high voltage switch cabinet is with electric mechanic/variable frequency switch, when the high voltage vacuum contactor KM2, closed KM3, motor for Δ connection, the motor rated voltage 3.465 KV, when electric mechanic frequency is run, high voltage vacuum contactor KM1, closed KM4 motor connected to the grid, directly through the power frequency ark directly by the power frequency startup into line.

4, PLC control box is mainly responsible for the logic chain and the compressor to communicate with the DCS system. When the inverter is ready and the power frequency into line after closing, if the DCS system signal unit, high voltage switch cabinet KM2, KM3 switch, automatic switch cabinet input variable frequency operation mode, the unit automatically preferentially activate inverter operation. Frequency control of motor speed closed-loop control is adopted in the system, the DCS control system by the compressor output speed given value (4 ~ 20 ma) for frequency converter and motor driven by a frequency converter smooth start, at the same time, the operation of the inverter output motor run/stop, failure, and motor current, power, such as water temperature signal to DCS system. When frequency conversion into the high voltage line in break-brake position or the transducer failure, if the DCS system signal unit, the high voltage KM1, KM4 switch, automatic switch cabinet input power frequency operation mode, the unit to enter the running state of the power frequency. PLC output unit running power frequency signal to DCS system.

5, water cooling system: frequency converter standard configuration using water, however, more air cooling mode in terms of the frequency converter

6, energy saving and the surge coordination control: hump type characteristics of the large capacity compressor surge problem is one of the important problems, system design must consider the inverter work normally, the system by frequency control of motor speed and the surge of the coordinated control, and as far as possible to reduce gas flow, at the same time to ensure that the flow is greater than the line safe operation flow, the system will not occur surge phenomenon, do a good energy saving and the surge coordination control effect.

Four, the system debug

Routine inspection:

1, system ACS1000 high voltage frequency converter for before they go out to do the strict no-load and load test, make the inspection before commissioning on electricity work is very simple, usually check job has the appearance and the external circuit connection check, logic check, IGCT check whole of dc withstand voltage test, frequency converter, etc.

On electricity: 2, inverter power inverter automatic startup after fan and internal circulating water in addition to the ion loop, the circulating water of electrical conductivity is one of the frequency converter allows the MCB switching conditions,

3, as part of the conventional debugging, motor run to identify the object ID. The motor nameplate on basic data input to the motor inverter, ID identification to manually start the motor running. ID once you start running, the whole recognition will run fully automatic. During the running of the ID identification, applied to the power inverter by monitoring the motor response to establish a mathematical model for motor, DTC controller is used in the model accurately extend the operation of the inverter and motor. The entire ID identification recognition operation takes about 2 minutes. Motor can run in low load ID identification recognition; But in order to achieve the best effect, should be the load from.

4, no-load and load operation: because the inverter is voltage type inverter, compared with the current type inverter, without the inverter parameter adjustment of different load conditions, debugging is simple, the actual charged operation debugging, empty load running first, and then loading operation and adjust related parameters to the best value. In the process of debugging, we use a DR