Enclosed Busbars Micro Positive Pressure Equipment Protecting Isolated Phase Bus Bar

Enclosed busbars micro positive pressure equipment

Closed busbars micro positive pressure device

Purpose and function of using closed busbar micro positive pressure device

1.Purpose: To improve the overall healthy operation level of the bus duct.

2.Function: The device generates a micro positive pressure inside the shell of the phase-isolated busbar slightly higher than the outside atmosphere, so that moisture, dust, salt mist, etc. in the outside can not enter into the shell of the phase-isolated busbar, so that working environment of the insulator, the shell and the conductors is always kept clean and dry. So as to ensure and improve the insulation strength of the bus duct to ensure safe and reliable operation.

It Prevents the impact of temperature changes. Breathing effect on the busway will be happened for the busbars in the north, hot and humid, and coastal areas due to changes in operating and shutdown temperatures and changes in day and night and seasonal temperature differences. The humid air with dust and smoke will enter into the busbar housing to reduce the insulation strength of the closed busbar, and bring hidden dangers to safe operation.

In summary, in order to improve the overall healthy operation level of the closed busway, a micro-positive pressure device should be put into operation. This device requires a certain air tightness of the closed busbar casing to ensure the positive pressure inside the busbar casing. Poor air tightness of the closed busbar casing will cause frequent or long-term operation of the device and increase energy loss and device failure rates.

Main technical parameters

Micro positive pressure device supporting equipment

Air source: (Must use oil-free air compressor or install oil filter before the device)

Oil-free air compressor: provide air source for the device

Air tank

……

Closed busbar

Micro positive pressure hot air circulation maintenance device

When the generator stops and the bus duct stops power transmission, the temperature of the air in the busbar decreases to its corresponding dew point temperature, dew condensation will occur. Even local freezing in the transformer side busbar for cold areas with a large temperature difference between day and night. This will seriously affect the safe operation of the busbar. In order to prevent dew condensation and freezing, the closed busbar micro positive pressure hot air circulation maintenance device operates the hot air maintenance function when the generator is stopped and the busbar stops transmitting power. It uses highly dry hot air to replace the air in the busbar, and quickly reduces the relative humidity of the air in the busbar, improve the insulation level of the equipment in the busbar, ensure the safety and success rate of re-inputting of the closed busbar for power transmission. And run the micro positive pressure air filling function when the generator is starting and the busbar is transmitting. The automatic operation of the hot air maintenance function is controlled by a humidity meter. When the humidity meter detects that the relative humidity of the air in the closed busbar has reached the setting value or higher, the micro positive pressure hot air circulation maintenance device automatically input the hot air maintenance function. When the relative humidity of the air drops below the setting value, the device automatically stops the hot air maintenance function. When the generator is starting and the busbar is transmitting, the micro-positive pressure inflation function automatically runs, and the micro-positive pressure function is automatically controlled by the humidity meter and time controller.

Technical parameters

1.Provide hot air temperature 50℃~80℃ (or set on site)

2.Dew point temperature of hot air≤-40℃(NPT)

3.Provide air source flow ≥0.6m3/min

4.Oil content of air source ≤15ppm (all oil free)

5.Dust diameter ≤1μm

6.Controlled by Siemens PLC or Omron PLC

7.Double modes automatic control of the system by humidity meter and time meter

Closed busbar air circulation drying device

The air circulation drying device is a new type of moisture-proof& anti-dew condensation device for the closed busbar, which can completely avoid the occurrence of wet& dew condensation inside the isolated enclosed bus duct, and effectively improve the operating safety of the generator set. It is an ideal upgrade and replacement product of a moisture-proof & anti dew device such as micro positive pressure device and hot air maintenance device, the device can be applied to new nuclear power, thermal power, hydropower units and reconstruction projects.

Working principle

The air circulation drying device takes the relative humidity of the air inside the busbar as the evaluation index. When the relative humidity value is higher than the setting value, the device automatically puts into operation, and the dry air enters the busbar from the phase A and C shells of the busbar through the connecting pipe. After entering phase B at the end of each circuit, it enters into the device, and after drying, it returns to the phase A and C shells of the busbar, forming a closed-loop drying system, which effectively improves the air dryness inside the busbar and prevents condensation from occurring. Each end of the circuit is provided with a dry air flow adjustment device to ensure the drying effect of each circuit. After the drying device is put into operation, the dew point of the air in the busbar can be maintained at about -30℃. The drying device is provided with two adsorption cylinders, one for adsorption, one for regeneration, and alternate conversion, and the conversion time is 6 to 8 hours.

Features

1.Adopting large-flow air closed circulation drying method to continuously circulate and dry the air in the busbar, which can keep the humidity in the busbar to a low level, and the requirements for the tightness of the busbar are relatively low.

2.Adopt precision humidity sensor to monitor and display the relative humidity inside the busbar in real time, and automatically input or quit the device according to the operating status of the busbar.

3."PLC" control, stable and reliable operation, high degree of automation.

4.The color touch screen is used as the human-computer interaction interface, which is convenient to operate and intuitive to display.

5. The device uses heated regenerated molecular sieve as the adsorbent, which has strong hygroscopicity and good repeatability.

6. Complete equipment production, simple and convenient on-site layout and installation.

7.The device has two operating modes, manual and automatic for options.

Since the air circulation drying device adopts a circulation drying method, there is no need to establish a micro-positive pressure to prevent the intrusion of external wet air, and the busbar sealing requirements are not high. At the same time, it can fundamentally remove the moisture in the air in the busbar, reduce the absolute humidity of the air, and prevent condensation. The drying device system uses connecting pipes to connect all the spaces in the busbar, including places where micro-positive pressure cannot reach, such as transformer risers, so that the air in the busbar is 100% dry without dead zones.

Main parameters

Power supply: Three-phase three-wire or three-phase four-wire 380 VAC 4.5KW

Air circulation drying capacity:≥45m³/h

Internal air dew point: up to -30℃

Relative humidity in the bus≤50%, can be set by yourself

Maximum water absorption: 9.4KGX2 (one cycle)

Intelligent common box enclosed bus duct

Dust removal and dehumidification device

Considering the heat dissipation factor, the common enclosure bus has a less tightness requirements, which does not exceed IP54, and generally does not consider to use the micro-positive pressure technology.

Intelligent common box enclosed bus duct dust removal and dehumidification device is divided into two types: outdoor rainproof type and indoor installation type. The outdoor rainproof type adopts rain proof structure of outdoor box transformer, it is suitable for 50m to 100m length outdoor enclosure bus dust and dehumidification. The indoor installation type is suitable for common enclosure bus with outdoor length of less than 50 meters. It is connected to the outdoor through pipes. It can automatically start dehumidification and drying on the eve of condensation on the insulator, and automatically stop drying when the humidity decreases. It is especially suitable for frequent start and stop, coastal or wet areas with lots of rain. When the rainy season comes, the outside humid air enters the busbar with the air, and even water ingress of the outdoor busbar in the rainstorm weather. Humid air has high relative humidity and large water content, which is easy to be the water condensation on the bus shell and insulators. The equipment in the common box enclosed busway is designed according to indoor standards and is prone to discharge short circuits, which will seriously affect the safe operation of the busbar. For power plants with large changes in the temperature difference between day and night, if there is a strong wind, the air contains a large amount of dust, the sand in the outdoor busway will increase, and the pollution level will increase. In foggy weather, the relative humidity of the air will increase, and the temperature of the outdoor busway at night will decrease. Dew condensation may occur on insulators of outdoor busbar, which will seriously affect the safe operation of the bus.

Our intelligent common box enclosed bus duct dust removal and dehumidification device has many functions of dust removal and dehumidification. It is suitable for humid outdoor environments that are often hit by heavy rain. When the bus stops transmitting power, and there is water condensation or water in the bus, and the environmental humidity is seriously exceeded, the thermometer controls the operation of the air-heat open-circuit dehumidification mode. The air is passed through dust removal, molecular sieve drying, heated and then send back to the bus. Continuous cycle dehumidification. It will stop when the humidity is reduced. This equipment has the dual drying effects of molecular sieve drying and temperature controlled hot air convection drying. Considering the need for heat dissipation during bus power transmission, the temperature-controlled heating unit is generally cut off, and the molecular sieve drying unit continues to dry the bus. The device has dust removal and dehumidification functions, which can remove dust and moisture inside the common box enclosed busway, and remove dust and moisture on each insulator and bring the dust and moisture to the outside of the common box busway, keep the inside of the bus clean and dry, effectively solve the difficulties of live maintenance of the common box bus, and meet the needs of unattended and automatic operation of the power plant or substation. Eliminate the difficulty of high-voltage live cleaning and maintenance.