SJD13 OIL-IMMERSED GROUNDING TRANSFORMER

Model: SJD13 series
Rated capacity: 400kVA
Voltage ratio: 10/0.4kV
Connection group: ZN,yn11
Short circuit impedance: 5.04%
Frequency: 50Hz
Technical standard: GB 20052-2020
Quality standard: ISO 9001:2015; ISO 14001:2015

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Grounding transformers, abbreviated as grounding transformers, can be divided into oil type and dry-type according to the filling medium; According to the number of phases, grounding transformers can be divided into three-phase grounding transformers and single-phase grounding transformers.

The function of a grounding transformer is to provide an artificial neutral point for systems where the neutral point is not grounded, facilitating the use of arc suppression coils or small resistance grounding methods to reduce the capacitance current to ground in the event of a grounding short circuit fault in the distribution network and improve the power supply reliability of the distribution system

-Low zero sequence impedance to ensure the output of zero sequence current;

-High excitation impedance to reduce no-load current;

-Low no-load loss to save energy consumption during daily operation.

This type of transformer adopts Z-type wiring (also known as tortuous wiring). The difference from ordinary transformers is that each phase coil is divided into two groups and wound in reverse on the magnetic column of that phase. The advantage of this connection is that the zero sequence magnetic flux can flow along the magnetic column, while the zero sequence magnetic flux of ordinary transformers flows along the leakage magnetic circuit. Therefore, the zero sequence impedance of Z-type grounding transformers is very small (about 10 Ω), while ordinary transformers are much larger. According to regulations, when using a regular transformer with an arc suppression coil, its capacity shall not exceed 20% of the transformer capacity. Z-type transformers can be equipped with 90% to 100% capacity arc suppression coils, while grounding transformers can also carry secondary loads in addition to arc suppression coils, which can replace station transformers and save investment costs.

1. Quality Management System ISO 9001: 2015

The operation of the entire Dongrun Electric system is strictly controlled and managed. This ensures the quality of the product at all stages, from receiving customer requirements to design, materials, production, installation, testing, packaging, delivery, and after-sales, all of which are operated under a strict and tight process.

2. Environmental Management ISO 14001: 2015

Dongrun Electric took the lead in applying the ISO 14001: 2015 environmental management system. The implementation of this process demonstrates Dongrun’s responsibility to a wide range of customers. Dongrun is committed to providing the most environmentally friendly high-quality technical products.

3. Certification Certificate ISO / IEC 17025: 2017

The ISO / IEC 17025: 2017 certification confirms that Dongrun’s technical quality meets the requirements of all specific international testing and calibration laboratory standards. All Dongrun products are fully tested in qualified laboratories before leaving the factory to ensure stable quality and provide customers with absolute peace of mind.