Airport constant current dimmer

LR-2000III type Airport constant current dimmer

LR-2000III type navigation aid constant current dimmer is a single chip microcomputer controlled thyristor type constant current dimmer, which is specially used for the control of airport runway navigation light series circuit.

Compliant specifications and standards

ICAO  Airport Design Manual Part V,

FAA AC 150/5345-10E  L-828 and L-829 ,

MH/T 6010-2017 constant current dimmer

Technical data

1) Technical parameters

    Table 1-1  

rated power	4,5, 7.5, 10, 15, 20, 25, 30kVA
Rated input voltage	Single-phase 220V/380V ± 15%
Rated frequency	50Hz ± 5%
Series loop current	Rated output current 6.6A
Remote control	Redundant CAN field bus, MOBUS/RS485, Profibus and parallel bus
Mean time between failures	More than 20000 hours
Brightness level	Five adjustable brightness levels
Harmonic current	The harmonic current of the dimmer is small, which does not affect the normal operation of other equipment

2) Constant current characteristics of dimmer

Under the following conditions, the output current is constant ( ± 1%):

  • From short circuit to 100% load

  • From 100% load to short circuit

  • rated voltage, rated frequency and ambient temperature change within the allowable range

  • 30% open circuit on the secondary side of the isolation transformer

3) power dimmer power factor Number

  At rated input voltage, rated load and maximum brightness level

  • Power factor ≥ 0.95 under the above conditions

  • Efficiency under the above conditions ≥92%.

4) Dimmer output transformer output tap

   • Rated load

   • rated load of 9 0% to the rated load of 5 to 0% , 5 groups of taps

5) Dimmer protection function

• 5% overcurrent protection for 5 seconds and 25% overcurrent protection for 1 second

• Light circuit is open for 2 seconds protection

• Power-off protection, the dimmer maintains the original working state when power is suddenly lost after power-on, and there is no need to restart when power is restored

• Prevent internal overvoltage and lightning protection

• Soft switch of dimmer to prevent current impact from damaging bulb protection

• Over temperature protection;

• Data protection during power-off;

• Protection against electric shock.

• Regulation failure protection

6) Dimmer noise

1 meter away from the dimmer , the noise is less than 45 decibels.

7) Dimmer display function

• Current, voltage and light level display of the light circuit (accuracy is not less than 1%)

• Fault indication

• Total running time and 5-level optical total running time display

• Insulation resistance value display of light circuit

• Communication status display

• Fault code display

The above displays are all digital displays.

8) Light cable insulation inspection

The dimmer has the function of monitoring the insulation to the ground. When the insulation resistance drops, there are warning and alarm signals.

9) Sound and light alarm function

• Light circuit open circuit alarm

• Light circuit short circuit alarm

• Insulation resistance of the light circuit drops and the light circuit ground alarm

• Light circuit 5% overcurrent and 25% overcurrent alarm

• Light circuit overvoltage alarm

• Light circuit undervoltage alarm

• Lamp failure alarm

Dimensions

600mm (length) × 600mm (width) × 1600 (1300) mm (height)

           

     

           

Dimmer structure           Dimmer waveform

Features

LR-2000Ⅲ type dimmer is a single host machine without backup model, which is mainly composed of low voltage distribution devices such as control cabinet, thyristor, contactor and booster transformer. The internal cooling is a self-cooling structure, and heat dissipation channels are reserved around and on the top of the cabinet. This dimmer can be used both in trenches and without trenches.

The control circuit of the dimmer is divided into different functional modules according to the function, and each functional module is inserted in the bus-style European-style chassis. This structure makes the dimmer have the following characteristics:

1) High constant current accuracy (accuracy is not less than 1%)

On the current and voltage sampling channel, select the AD536 true effective value sampling chip of AD company, which can convert the discontinuous current after thyristor chopping to true effective value, the maximum error is 5mV, and the A/D conversion part adopts 10 bits If the converter is calculated according to the load current of 10A , the sampling accuracy can reach 10A /1024, which is approximately equal to 0.01A and is much higher than the constant current accuracy of 1%.

In the control, we use a 16-bit microcontroller to divide the half cycle of the commercial power into 5000 points for control, and the control accuracy can reach 380V/5000=0.076v

Through the above measures, a constant current accuracy of 1% of the dimmer is ensured:

2) High reliability guaranteed by advanced design and process

• All key components are imported and undergo strict aging to ensure reliability.

• Each functional module has an independent CPU system, distributed control maximizes reliability.

• circuit board is strictly moisture-proof, dust-proof and anti-corrosive, and can adapt to various environments.

• The software and hardware use advanced anti-interference measures to ensure that the equipment can work 24 hours a day.

In terms of hardware, the input part is equipped with isolation transformers and filters, which can not only prevent malfunctions and alarms due to external influences. It will not interfere with the normal operation of other electrical and electronic equipment due to the dimming cabinet; a surge arrester is installed in the high-voltage part; a filter is installed in the analog sampling part to prevent current fluctuations; a filter is installed in the switching part to prevent misoperation; Reliable shielding and grounding, blocking space interference.

The software part, numerical filtering technology, eliminates random interference; instruction redundancy and watchdog technology prevent the program from flying.

3) High degree of standardization, strong versatility and high 

interchangeability

The dimensions of all functional modules are completely the same, and the modules of each machine can be completely interchanged. Since the chassis is a standardized product and adopts the bus mode, each functional module can be inserted at any position on the bus. Good interchangeability allows each machine to share the least spare parts, and the running cost is low.

4) Complete scalability

At present, only 4 slots are used on the bus board of the dimmer, and there are still 2 to 3 free board positions, and the bus is only half used. It is intended for the functional modules developed with the development of technology in the future. Leaving complete expansion space. For example, the remote diagnosis function module realized through the Internet is being developed.

5) Convenience of use and maintenance

The operation function can be realized by only one knob, without misoperation, and at a glance. Maintenance is displayed through self-diagnostic functions on various functional modules, and can also be judged through the interchange of standard modules. It only needs to plug and dial to replace a module, and it can be completed within 10 seconds.

6) Configuration flexibility, convenient for users to choose

Each functional module is an optional function. The user can freely choose according to the needs. The functional module can be easily inserted into the bus at any time. The customer's decision-making has no worries.