Suitable for distribution systems in large and medium-sized industrial and mining enterprises with large load fluctuations and frequent power factor adjustments, such as 6KV and 10KV substations. This device automatically switches capacitor banks based on factors such as system voltage and reactive power deficit, through comprehensive calculation, to improve voltage quality, improve power factor, and reduce line loss. This device is suitable for unmanned substations where the harmonic voltage and current meet the allowable values specified in the national standard GB/T14548-93. If the on-site harmonic conditions exceed the standard, 1% -13% reactance can be equipped according to the situation to resist harmonic entering the compensation equipment.
Structure and basic working principle
The high-voltage reactive power automatic compensation device consists of a controller, high-voltage vacuum switch or vacuum contactor, high-voltage capacitor bank, reactor, discharge coil, lightning arrester, and some necessary protective auxiliary equipment. The digital high-voltage reactive power automatic compensation controller is based on the nine zone diagram combined with fuzzy control principle, and determines whether to switch the capacitor bank according to the requirements of voltage priority, load reactive power, and limited switching times, so that the bus voltage is always within the standard range, ensuring that the maximum loss is minimized without compensation. Within the allowable voltage range, switch the capacitor bank in place at once according to the reactive power requirements of the load. Before investing in capacitors, budget for the voltage increase. If it exceeds the standard, reduce the capacity investment or do not invest. When there is an abnormal situation, the controller issues a command to exit all capacitor banks and also emits an audible and visual alarm. After troubleshooting, manually release the alarm before returning to automatic operation mode.
Technical characteristics
1. Voltage priority
Automatically switch capacitors according to voltage quality requirements. When the voltage exceeds the maximum set value, gradually cut off the capacitor bank until the voltage is qualified. When the voltage is lower than the minimum set value, gradually put the capacitor bank into operation while ensuring that it is not overloaded, so that the bus voltage is always within the specified range.
2. Reactive power automatic compensation function
Under the principle of voltage priority, the capacitor bank is automatically switched based on the reactive power of the load, so that the system is always in a state of minimum reactive power loss.
3. Intelligent control function
Before automatically issuing action commands, first inquire about all possible out of limit values that may occur after the action, in order to reduce the number of actions.
4. Abnormal alarm function
When the relay protection action of the capacitor control circuit refuses to move and the controller automatically locks the automatic control of the reorganized capacitor.
6. Fuzzy control function
The implementation of comprehensive control principles when the system is at the high end of the qualified voltage range and in a specific environment is a difficult point in the design of this series of products. Frequent actions caused by various factors on site, such as configuration environment, power supply status, action time, and user restrictions on the number of actions, are the most concerning for users. The application of fuzzy control takes into account these many factors to reasonably solve this "blind spot".
7. Comprehensive protection function
Each device is equipped with switch protection (optional), overvoltage, undervoltage, overcurrent (short circuit) and zero sequence relay protection, double star unbalanced protection, fuse overcurrent protection, zinc oxide lightning arrester, grounding protection, quick break protection, etc.
Main technical parameters
1. Rated voltage (AC) 6KV, 10KV
2. System voltage sampling (AC) 100V (PT secondary line voltage)
3. AC current sampling 0-5A (if PT takes the secondary A and C phase line voltage on the 10KV side, CT should take the B phase current)
4. The voltage setting value is adjustable from 6 to 6.6KV and from 10 to 11KV
5. The action interval time is adjustable from 1 to 60 minutes
6. The power factor setting value is adjustable from 0.8 to 0.99
7. Current transformer adjustable from 50 to 5000/5A
8. The action requires a stable system time of 2 to 10 minutes, which can be adjusted
Usage environment
1. Environmental temperature -15 ℃~+45 ℃
2. Relative humidity ≤ 85%
3. Altitude ≤ 2000m (High prototype is used for elevations above 2000m)
4. There are no explosive or flammable hazardous materials in the surrounding medium, no gases that can damage insulation or corrode metals, no conductive dust, and no severe vibrations or bumps at the installation site.
5. The power supply complies with national standards and does not have strong harmonic components.