Shore power supply for ship

Abstract

The invention provides a shore power supply for a ship, which belongs to the technical field of ship power supplies and is used for solving the problems that power cannot be supplied remotely or supplied to large-sized ships, uninterrupted parallel running of chips cannot be realized and the like. The shore power supply for the ship comprises a switch cabinet, a shoreside high-voltage frequency conversion device, an onboard voltage reducing device and a synchronous grid-connected device, wherein the shoreside high-voltage frequency conversion device is connected with the switch cabinet; the high-voltage side of the high-voltage frequency conversion device is connected with the high-voltage side of the voltage reducing device through a high-voltage cable; the low-voltage side of the voltage reducing device is connected with the synchronous grid-connected device; three-phase high-voltage alternating current can be subjected to cutting, phase shifting, rectifying and inverting by using the high-voltage frequency conversion device to obtain needed frequency; and three-phase alternating current which is subjected to frequency conversion and voltage reduction can be seamlessly combined into a power grid of the ship, and the power supply of the ship can be switched off by using the synchronous grid-connected device. By adopting the shore power supply, remote power supply or power supply for large-sized ships can be realized, automatic grid-connected operation can be realized, the ship runs unremittingly, and normal production operation is not influenced.

Description

technical field [0001] The invention belongs to the technical field of ship power supply, and relates to a shore power supply for ships. Background technique [0002] Large ships, especially oil tankers and container ships, usually use fuel oil products (mostly heavy oil and diesel oil) to generate electricity when they are docked to meet the electricity demand of the power supply system on board the ship after berthing. electricity. Fuel products such as heavy oil and diesel produce a large amount of sulfide and nitrogen oxides during the combustion process, causing serious pollution to the surrounding environment. At present, the power supply of the domestic power grid is 50HZ, while the power supply of foreign ships is 60HZ. If the land power grid is used for direct power supply, the difference between the power supply system of the port and the ship will definitely have a serious impact on the ship's electrical equipment. In such an environment, a marine shore power su...

AI Technical Summary

Problems solved by technology

[0003] In order to meet the power supply demand of the land power grid for ships in port, there are currently two highly feasible high-power shore power supply solutions: a low-voltage inverter high-power shore power supply scheme, the principle of which is to combine the power grid three-phase 50HZ high The piezoelectric is first stepped down to 380V / 50HZ by a transformer, then input to the low-voltage shore power supply, rectified and inverted by the low-voltage inverter system to output at 60HZ, and then boosted to 60HZ by the power transformer to supply power to ships in port. The low-voltage shore power supply technology has the following deficiencies: 1. In the low-voltage inverter shore power technology, there are many parallel inverter modules required for the high-capacity shore power supply, and the complex load of the ship needs to be directly started by a high-power motor. The reliability of the low-voltage inverter is greatly reduced; 2. The low-voltage inverter pulse uses 6-pulse rectification, and the low input power also causes great pollution to the power grid

This high-voltage inverter shore power technology does make up for some of the shortcomings of the above-mentioned low-voltage inverter technology, but it also has some shortcomings: 1. In the power transmission problem, the actual ship is still far away from the shore when it docks. The larger the ship, the farther the distance from the shore is, sometimes reaching more than 500 meters. If a low-voltage 440VAC power supply is used to connect to the ship, the current of the connecting line will be large, the voltage drop will be high, and the line loss will be large, so that high-power power supply cannot be transmitted to the ship. Loads can only be used for short distances less than 200 meters and marine loads less than 400KVA. It is unreasonable to design power supply for ships with long distances or large loads.

2. The power conversion of the system is not ideal. After the ship docks, when the shore power is used for switching, there will be a few minutes of switching time for the equipment on the ship to lose power, and some equipment on the ship cannot be powered off. It will cause inconvenience to the operation of the ship

3. The control method and circuit protection are not perfect, the performance is not stable enough, and the modular design is not used in the circuit design, which brings inconvenience to circuit maintenance and repair

4. The power unit module that directly converts the three-phase current of the high-voltage power grid into direct current requires a large number of components, and the low input power will cause great pollution to the power grid

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