马克威尔

The electricity load of urban rail transit can be divided into four major electricity groups according to its different functions;

1. The traction load required for the operation of electric buses;

2. Power and lighting electricity required for other buildings such as stations, sections, depots, control centers, etc., such as:Ventilators, air conditioners, escalators, elevators, water pumps, lighting, AFC systems, FAS,BAS, communication systems, signal systems, etc.

3. High order harmonics generated by traction rectifier inverter devices (11th, 13th, etc.);

4. Secondly, there are a large number of nonlinear loads in the substation (3, 5, 7, etc.); And with the upgrading of equipment and the increase of passenger flow, the harmonic components and types are increasing year by year, and the dominant harmonic has a continuous increasing trend; Due to the installation of traction loads on the 10KV or 35KV side, a 12 pulse rectifier device is generally used, which will reduce the harmonic content; If the harmonic content does not exceed the standard, it can be considered to only treat the harmonics generated by the second largest power group on the low-voltage 0.4KV side.
Quality evaluation

1. Improve the safety and reliability of the low rail transit power supply system;

2. Energy conservation and consumption reduction, reducing the operating costs of rail transit;

3. Safely improving power factor; Avoiding fines from power supply departments for force assessment;

4. Reduce the damage of harmonics to electrical equipment and ensure the stable operation of distribution equipment and reactive power compensation devices;

5. Ensure the stable operation of the intelligent control system and operation command system;
Accessory project

Adopting the [passive filtering+active filtering] scheme for harmonic control and reactive power compensation in different functional areas

1. Select a fast filtering compensation device: safely increase the power factor;

2. Selecting passive filters: To control a large number of 5th, 7th, 11th, and 13th harmonics, to avoid damage to communication and electrical equipment caused by harmonics, and to reduce the loss of power consumption caused by harmonics;

3. Select active filter: eliminate interference caused by other harmonics on important equipment and functional loss of power;

4. Select a harmonic voltage suppressor to suppress 5th, 7th, 11th, and 13th harmonic voltages.