| Brand | ROCKWILL |
| Series | S |
| Rated primary voltage | 15/20/30 kV |
| Power | 50-2000 kVA |
| No-load loss | 145-2600 W |
| Load loss | 1350-25500 W |
ROCKWIL Electric strives to bring our customers the latest technology and competitive pricing and best service for distribution automatic.With the development of the power industry, driven by urbanization, equipment intensification, technological advancements, and the urgent need for scenario adaptability, Rockwill has successfully developed the Top-Mounted High/ Low Voltage Bushing Transformer (commonly known as the H59 Distribution Transformer), leveraging years of electrical design experience and integrating global advanced technical concepts.
The H59 refers to a power transformer where both the high-voltage and low-voltage bushings are vertically installed on the top of the unit. This structural design allows all high- and low-voltage leads to be routed through the top, making it suitable for scenarios with strict lateral space constraints or requiring vertical busbar connections. It is a common type of oil-immersed transformer.
| Rated primary voltage（kV） | Power (kVA) | No-load loss (W) | Load loss (W) | Impedance voltage (%) | Efficiency 75% cosΦ=0.8 | Efficiency 75% cosΦ=1 | Efficiency 100% cosΦ=0.8 | Efficiency 100% cosΦ=1 |
|---|---|---|---|---|---|---|---|---|
| 15/20/30 | 50 | 145 | 1350 | 4 | 97.07 | 97.65 | 96.40 | 97.10 |
| 100 | 210 | 2150 | 4 | 97.69 | 98.14 | 97.13 | 97.69 | |
| 160 | 460 | 2350 | 4 | 98.18 | 98.54 | 97.85 | 98.27 | |
| 250 | 650 | 3250 | 4 | 98.37 | 98.70 | 98.09 | 98.46 | |
| 400 | 930 | 4600 | 4 | 98.56 | 98.84 | 98.30 | 98.64 | |
| 630 | 1300 | 6500 | 4 | 98.71 | 98.96 | 98.48 | 98.78 | |
| 800 | 1220 | 10700 | 6 | 98.51 | 98.81 | 98.17 | 98.53 | |
| 1000 | 1400 | 13000 | 6 | 98.57 | 98.85 | 98.23 | 98.58 | |
| 1250 | 1800 | 16000 | 6 | 98.58 | 98.86 | 98.25 | 98.60 | |
| 1600 | 2200 | 20000 | 6 | 98.62 | 98.89 | 98.30 | 98.63 | |
| 2000 | 2600 | 25500 | 6 | 98.61 | 98.88 | 98.27 | 98.61 |
① LV cable box ② Plug-in HV bushing ③ Lifting lug ④ Oil drain valve ⑤ Roller ⑥ Nameplate ⑦ Dry-type LV bushing ⑧ Integrated protection device
According to the current Chinese national standard GB 20052-2020, the Level 1 energy efficiency model for 10kV oil-immersed distribution transformers is S22 (featuring amorphous alloy cores or high-quality electrical steel strips). Level 2 efficiency corresponds to S20, and Level 3 to S13. Since H59 are typically not rated at the S22 level, you should select the S22 if you are pursuing maximum energy efficiency.
As 10kV oil-immersed transformers, H59 must meet the Level 3 energy efficiency limit of GB 20052 to be legally sold. Most standard products reach Level 3 (equivalent to the S13 level). However, as they are not specifically positioned for extreme energy savings, they usually do not apply for Level 1 or Level 2 energy-saving certifications. If a project strictly requires Level 1 efficiency, the S22 model should be selected.
H61 is a small-capacity (≤160kVA) hermetically sealed pole-mounted distribution type with epoxy plug‑in bushings and no oil conservator, while H59 is its upgraded version, covering 50–800kVA+ with improved insulation and heat dissipation.
