Power transmission scheme of refitting low altitud

The working principle of sliding contact line power transmission is: set up a sliding contact line power supply line powered by urban electricity in the container yard. When the gantry crane operates in the container area, turn off its own diesel generator set, and the required power is supplied by the sliding contact line. The gantry crane moves along the sliding contact line to realize the work coverage of the whole container area. When the gantry crane needs to be transferred to another box area for operation, unplug the plug, cut off the connection between the power supply and the gantry crane, and change the power supply from the low-power diesel generator set to realize the transfer. After being transferred to the designated storage yard, the diesel generator set stops working, plug in the plug and switch the power to the sliding contact line again

the trend of power supply line is: introduce high-voltage power supply (e.g. 10K VI) from the power supply station to the on-site storage yard, and convert it into the voltage required by the gantry crane (e.g. 440V) through the transformer in the storage yard to the power cabinet in front of each sliding contact line. The power cabinet is generally equipped with a circuit breaker for protection. The circuit breaker is directly connected to the copper or aluminum sliding line erected on the stand for 3-phase and 4-wire power supply, and the power is supplied to the tally room of the gantry crane through the collecting trolley and power supply cable, The plugs and sockets in the manager's cargo room are connected to the machine. The gantry crane cart is equipped with a traction device to pull the sliding contact trolley to slide along with the gantry crane cart, so as to realize the mobile sliding contact power supply mode of the gantry crane. The transmission mode of sliding contact line is similar to that of urban trolleybus

the capacity of the transformer in the yard is calculated as follows: if the power supply capacity of one gantry crane is 400 KVA, a total of L 5 electric gantry cranes are connected to the sliding contact line, and the overall capacity of the gantry crane is 400 × 15=6000 kVA。 Considering L 5 gantry cranes, but this is a major challenge. Some cranes are rising and the scale of air-cooled coolers should be cleared regularly, some are descending and some are in standby state, so a full synchronization coefficient should be taken in the calculation. According to the actual test and experience, the synchronization coefficient is 0.2 ~ O_ 3. Therefore, the total capacity of on-site power supply transformer should be l 800 KVA in theory and 1 600 KVA in practice

at present, the height of low altitude sliding contact line is generally set in two ways: one is about 3.5 m, mainly considering the safety needs; The other is about 2.5m high, mainly considering the convenience of maintenance on the ground; The height can be selected according to the needs of each wharf. In addition, there are two layout modes of sliding contact lines: one is single row power supply mode, that is, only one row of sliding contact lines are set on the vertical frame for power supply; The other is the power supply mode of strong row, that is, the left and right rows of sliding contact lines are set on the vertical frame for power supply, and each row is equipped with three-phase and four wire copper sliding lines for twice the number of gantry cranes. The working state of this gantry crane is known as "back-to-back" working mode

1 features

(1) the sliding line frame occupies the storage yard space and the layout requirements are strict

(2) high safety requirements. In addition to certain anti-collision measures, relevant safety rules and regulations shall be stipulated

(3) generally, the power supply area shall be closed, and protective devices and prompt signs shall be installed to prevent collision

(4) there are certain requirements for the operation performance of the gantry crane. In addition to the good deviation correction ability of the gantry crane, deviation correction and anti-collision safety protection measures shall also be set

(5) generally, gantry crane traveling deceleration protection and end limit protection are set at the end of the whole sliding contact line to prevent the gantry crane from leaving the power supply area of the sliding contact line

(6) after a certain period of operation, the carbon brush needs to be replaced, but the workload is low. For safety reasons, Party A often needs a certain amount of maintenance

2 advantages

(1) the configuration is relatively simple, the power supply quality is high, and the loss of transmission line is less. After field test, the voltage drop from sliding contact line to gantry crane is almost zero

(2) the gantry crane has less change momentum. It only needs to install a full socket, plug in the power supply of sliding contact line and some interlocking protection

(3) the follow-up gantry crane in the same site can work after it is directly connected to the power supply cable on the sliding contact line without additional cost

(5) the investment cost is higher than that of the cable drum transmission scheme, but it is lower than that of the overhead sliding contact line transmission scheme, but it is not allowed to break, which is a particularly serious accident. The investment recovery period is about 3 ~ 4 years

3 disadvantages

(1) generally, the sliding contact line is discontinuous between the two boxes in the storage yard. When the gantry crane changes the box area and crosses the river, it needs to manually plug in and pull out the plug and power on again

(2) the gantry crane is transferred for 90. The power supply of the engine is required to support the gantry crane's crane to walk

(3) safety problems need to be tackled frequently