ZWJ axis displacement monitoring device for power station automation components

ZWJ axis displacement monitoring device for power station automation components

ZWJ axis displacement monitoring device for power station automation components

I. Overview

ZWJ intelligent axis displacement monitoring instrument is a unit structure spindle axial displacement monitoring instrument. The monitoring device uses a microcontroller as the core processor, equipped with non-contact eddy current displacement sensors and preamplifiers, to monitor the axial displacement of the main shaft during the operation of the hydroelectric generator set.

2、 Characteristics

Using a microcontroller as the core processor unit, it has strong data processing capabilities and high accuracy;

Output standard analog signals corresponding to the display range;

Provide alarm status display and normally open contact output, and the two-level alarm values can be set separately;

■ Equipped with power-off memory and automatic parameter protection function;

■ Switchable display of gap voltage values for eddy current displacement sensors;

■ Comprehensive system self checking function;

Provide working power supply for the transmitter.

■ Input signal: One channel of eddy current sensor signal;

Measurement range: 0-20.00mm (or determined by the user);

Measurement accuracy: ± 0.01mm;

Sensitivity: 5V/mm (or 2.5V/mm);

Frequency response: 0.5Hz to 250Hz;

Display mode: 8-bit digital tube display;

■ Provide sensor working power supply: DC ± 12V;

Output analog signal: DC4-20mA (load resistance ≤ 525V);

Output alarm signal: Contact form: normally open Contact capacity: AC220V 5A/DC24V 5A

Alarm setting value: two-level alarm output (set arbitrarily within the range);

■ Instrument working power supply; AC220V±10％ 50Hz；

Power consumption: 10W;

■ Operating environment: Temperature range of 0 to+45 ℃; Relative humidity ≤ 90%

The SLH type liquid level switch produced by Qingyi Company is used to control the liquid level of the upper guide, thrust, water guide oil tank, and return oil tank of the unit. When the oil level is higher or lower than the set value, the liquid level switch sends corresponding signals. This liquid level switch has been used for a long time in multiple power stations both domestically and internationally, and its operation is reliable.

The top cover liquid level switch adopts the MBBC heavy hammer type liquid level switch produced by XACLAKE company, which monitors three liquid levels, adjusts the action value arbitrarily, has a large contact capacity, and operates on the principle of gravity. Overcome the problem of easy jamming and refusal to move of the original float type liquid level switch.

The PR-46W level transmitter is used to measure the liquid level of the oil tank and top cover, with high accuracy and good stability. Its main feature is for measuring the oil level of small ranges in the oil tank. Measure the liquid level of the top cover. When using and installing, attention should be paid to waterproofing. Connect the cable to the terminal box to avoid water entering the air duct of the cable, which may cause it to be unusable.

The speed measurement system consists of two parts: PLC-4S electrical speed switch and ZKZ-4 mechanical speed switch produced by XALTHYYXGS company. The speed measuring device is installed on the top of the generator and generates a pulse signal proportional to the unit shaft speed through a gear plate and a zero speed sensor. The characteristic of this speed measurement system is that the amplitude of the signal is constant, and even at very low speeds, the signal will not be lost. The sensor signal is sent to the electrical PLC speed signal processing device; Provide 13 electrical contact signals and crawling contact signals with adjustable action values (1% -200nr); Two 4-20mA analog outputs corresponding to the 0-200nr range of the unit; Action parameters can be modified through the liquid display panel; 1 set of mechanical speed switches, acting on the unit's overspeed protection; Equipped with overhead lights for unit operation; Four mechanical switches can be provided according to user requirements. This device has been used in multiple power stations.

Another set of ZKZ-2A speed signal device installed on the instrument cabinet of the water turbine is used to receive PT signals, output 6 adjustable electrical contact signals and 1 4-20mA analog signal corresponding to the 0-200nr of the unit.

The low pressure air control of the unit (such as unit braking, maintenance shrouds, and pneumatic shear pins) adopts XACLAKE's JZFG series solenoid valves. This valve is a single coil, fully injection molded vacuum sealed. Can be powered on for a long time and operates reliably. Solved the problem of coil damage caused by humid environment. By selecting, the opening and closing form of the valve can be determined. Manual operation. The monitoring of the cutting pin of the turbine guide vane by this unit adopts pneumatic method. Under normal circumstances, compressed air enters the blind hole of the water turbine guide vane shear pin through solenoid valves, ring pipes, and hoses, and the pressure switch sends a signal to the monitoring system that the shear pin is normal. When the unit is in operation and a shear pin is cut, compressed air is released from the broken shear pin. The air pressure in the loop decreases, and the pressure switch sends an alarm signal. Close the solenoid valve and cut off the cutting pin air source. This system fundamentally avoids the electrical grounding short circuit that is prone to occur in the original electric mode, improving the reliability of the system.

Install MLK-1 displacement sensors and domestic position switches next to the turbine unit and cylinder valve relay, as well as on the recovery mechanism. The characteristics of this displacement sensor: The guide vane relay displacement sensor uses a non-contact magnetostrictive displacement transmitter. Due to the non-contact between the moving magnet and the sensor, no wear occurs, which is conducive to long-term use; High precision and protection level; Easy to install; The measurement value can be adjusted within a certain range; Measurement signals are used for monitoring and unit speed control devices; Different action points can be set according to the needs of control, and the on/off electrical signals are provided to the monitoring system. On domestic and foreign units. More transmitters that use this principle. Domestic position switches are difficult to adjust. Due to factors such as large size, some power stations have been replaced by non-contact linear position switches.