| Brand | ROCKWILL |
| Model NO. | Customization Three - phase 11kV 20kV 22kV 30kV grounding/earthing transformers Original Manufacturer |
| Rated voltage | 22kV |
| Rated frequency | 50/60Hz |
| Series | JDS |
Description
As a pioneer and the first dedicated original manufacturer in China's earthing transformer industry, decades of in-depth technical cultivation have enabled us to accumulate strong strength and even establish the original standards for industry development. From breakthroughs in core technology R&D to large-scale mass production and delivery, we have built an end-to-end independent ecosystem. Leveraging leading and stable product performance as well as extremely reliable quality, we have become a trusted choice in the field of power grid construction.
This three - phase 11kV/22kV grounding transformer is tailor - made for medium - voltage power grids. By creating an artificial neutral point, it accurately achieves the grounding protection function and is suitable for various distribution system scenarios. When facing single - phase grounding faults, it can effectively handle them, building a solid defense for the stable operation of urban power grids and industrial power facilities, and ensuring the reliable power supply of the power system.
Main technical parameter
Some of these earthing transformers cover voltage levels including：3.3kV / 6kV / 11kV / 15kV / 20kV / 22kV / 30kV / 33kV / 34.5kV / 36kV / 44kV / 66kV / 88kV / 110kV / 132kV / 145kV / 150kV / 220kV / 275kV / 330kV / 400kV, etc. The current withstand time ranges from 1s, 2s, 3s, 5s, 6s, 8s, 9s, 10s, 30s, 60s, 1hour to 2hours, and customization is available.
Number of phases |
Three rows |
Output voltage |
400V |
Frequency |
50/60Hz |
Input voltage |
11kV 20kV 22kV 30kV 33KV 34.5kV 36kV |
High pressure rating |
11KV/22KV/33KV |
Low pressure rating |
0.4 KV |
Number of coils |
Three Windings |
Link category |
Dyn11 Yyno |
Coil structure |
toroidal |
Certification |
IEC60076 |
Insulation level: |
Dyn11 Yyno |
Application |
Industrial Equipments |
Standard |
IEC60076 |
Use |
Power transformer |
Class |
Oil - Immersed Transformer |
Product name |
Grounding Transformer |
Application Environment Description
Neutral Grounding Systems：Suitable for ungrounded, resistance-grounded, or arc-suppression-coil grounded medium-voltage distribution networks. Limits fault current and improves power supply reliability.
Harsh Physical Environments：IP54/IP56 protection rating, resistant to salt mist and dust. Suitable for altitudes up to 3000m and ambient temperatures from -25°C to +45°C.
Space-Constrained Locations：Compact dry-type design suitable for confined spaces such as underground substations, data centers, and ship engine rooms.
New Energy and Industrial Applications：Neutral grounding protection for systems including wind/solar power plants, rail transit, mining facilities, and oil platforms.
Special Electrical Environments：Compatible with systems containing harmonic pollution, frequent start-stop loads, and smart grids requiring coordination with protection devices.
Zero-sequence impedance is a key parameter that determines the magnitude of ground fault current, directly affecting the sensitivity and reliability of relay protection. Its function is to "accurately control the amplitude of fault current" — ensuring that the fault current is large enough to trigger the protection action, while avoiding excessive current that may damage equipment.
Fault withstand time refers to the maximum time that an earthing/grounding transformer can withstand the thermal and mechanical stresses generated by fault current without damage under rated short-time capacity. It is the core basis for insulation and structural design. The IEEE 32 and IEC 60076-5 standards specify four types of standard durations: ① 10 seconds: suitable for fast-acting protection systems (such as optical fiber differential protection), where faults can be isolated within 10 seconds; ② 30 seconds: the most mainstream withstand level, suitable for the relay protection action time of most distribution networks and transmission systems; ③ 60 seconds: used for old systems or complex power grids with long protection action time; ④ 1 hour: only applicable to high-resistance grounding systems, where the fault current is small but long-term monitoring is required.
"Short-time capacity" is a core performance indicator of earthing/grounding transformers, referring to their ability to safely carry the maximum ground fault current within a specified time (such as 30 seconds). This is determined by their operating characteristics of "short-time operation during faults and light load or no-load during normal operation".
kVA=3×V×I, where V is the system phase voltage and I is the maximum ground fault current. For example, for a 110kV system (phase voltage about 63.5kV), if the maximum ground fault current is 100A, the 30-second short-time capacity is 3×63.5×100≈19050kVA (19.05MVA).<meta />
