The low voltage filter dynamic reactive compensation equipment of our company is used in the inductive load with serious harmonics below 10KV (such as DC rolling mill, spot-welder, lift, etc). According to load nature, single-tuned filters channel is selected to filter power harmonics so that the distortion factor of voltage and current meet international requirement (GB/T-14549-93). This can improve power supply quality, reduce electric energy loss and improve enterprise economic benefit.
The products are widely used in industrial and mining enterprises, oil fields, ports and pier, residential quarters and rural power network. Controllers are used to track system load for automatic reasonable switching without the problem of switching oscillation, reactive power releasing to maintain system power factors at the best state. The switching mechanism may select one type of contactor, silicon controlled or composite switch switching to meet the requirement of different power grid environment on switching mechanism.
The national limit value of harmonic content in utility grid---selected from GB/T 14549-93
Nominal voltage of
distortion of voltage
|Each harmonic voltage ratio (%)
Dynamic filter compensation device of rolling mill
2.Reactive compensation and harmonic suppression equipment for aluminum profile oxidation and electrophoresis production lines
1、Special 210V, 315V, 400V, 600V, 900V and 1300V single-phase filter capacitor.
2、Quality filter reactors.
3、Silicon controlled switching unit device.
4、PLC controller and 7 inches and 14 inches color touch screen.
1.Low voltage dynamic filter reactive compensation includes three types: three-phase compensation, three-phase separate compensation and combined compensation and separate compensation.
2.According to actual load condition, in consideration of compensation effect and cost, select the compensation mode reasonably to solve the contradiction between compensating reactive power, three-phase imbalance and three-phase separate compensation and cost so that user’s input cost is optimal.
3.The mode of three-phase compensation is adopted for the system with basic three-phase balance. The compensation effect is good with low cost.
4.The mode of three-phase separate compensation is used for system with serious three-phase imbalance. This can resolve the problem of excessive compensation of certain phase and under compensation of another phase in three-phase unbalance system. But the cost is high.
5.For system where three-phase imbalance is not serious, the mode of compensation and separate compensation is used. This can avoid over compensation and under compensation and has low cost relatively.
1、 Use of silicon controlled as hurl-slices switch can achieve contactless automatic switching of filter without impact of switching in rush current and arc reignition. Re-switching may be performed without the need for discharge. The service life of switch and capacitor will not be affected due to continuous and frequent switching. The response is quick with low noise.
2、Adoption of PLC + touch screen achieves smart control and simple and convenient operation. The display screen may shows voltage, current, harmonics and other parameters in a real-time manner. It is flexible to set the menu by selecting harmonic elimination mode, reactive compensation mode, or simultaneous compensation mode of harmonics or reaction. Ratio of transformation and polarity of current transformer and the capacity of all compensation sub-circuits are set with use of software. Record of accidents and event record are performed in a real-time manner. The response time or dynamic compensation is ≤20ms.
3、Adoption of optimal double close-loop technology ensures accurate harmonic detection, high filtration rate, quick dynamic response, wide elimination scope of harmonics. The equipment itself is provided with perfect protection mechanism and smart control method so that they can detect operation condition of all parts automatically and limits the current automatically according to temperature to ensure long-term operation of equipment. At the same time, it avoids resonance with user’s system to ensure safe operation of users to a greatest extent.
4、For large scope of reactive power compensation (inductive and capacitive), the optimal strategy of harmonics and reactive compensation is adopted to make treatment of power quality of users reach the optimal state. It may be combined with traditional passive filter compensation device for use. The unique control algorithm ensures perfect combination between them.
5、No need to carry out complicated power grid analysis; simple design and selection, easy installation and operation; flexible inlet wire mode enables you to select top entry or bottom entry. If special transformer is selected, it may be used at occasions with higher voltage.
6、There is no need for specially-made current transformer and there is no special requirement for ratio of transformation of current transformer.
7.With over current protection, over heat protection, eliminate the 5th, 7th, 11th and 13th harmonics.
8.Total harmonic distortion of voltage (THDu) is reduced below 5% of national specified value.
9.The harmonic cornet injected to 10KV utility power grid is less than the permissible standard of the country.
10.Power factor COSΦ＞ 0.95 (generally to 0.95-0.99)