Place of application 
Capacitive-type voltage transformers are used as large-scale voltage converters and also for supplying standard, usable voltages in various monitoring, measurement and protection installations and, at the same time, for isolating protection and measurement equipment from high system voltages. They are also used to provide high frequency communications in electrical systems.
Execution
- Unom: from 110 to 750 kV
- Up to 6 secondary windings
- All measuring and protection accuracy classes with excellent resistance to network transients
- Hermetic system for compensating oil expansion with a stainless steel bellows
- Equipment for supporting high-frequency communications
Design
The paper insulation of the electromagnetic device is dried under high vacuum and impregnated with highly inhibited, degassed and dried mineral oil.
The tank is made of aluminum alloy or high quality steel, which is protected by hot-dip galvanizing and optionally repainted for long-term corrosion resistance.
A secondary terminal box is installed on the body of the electromagnetic device, along with other accessories such as oil indicator, indicating shields, oil sample valve, lifting lugs, and grounding clamps.
High Frequency Communication Equipment
Each capacitive voltage transformer is equipped with an external high frequency (HF) terminal located on the bushing on the tank of the electromagnetic device. This clamp allows each capacitive voltage transformer to be used as a coupling capacitor at any stage of operation.
On request, the RF clamp can also be placed in the secondary terminal box. In addition, RF communication equipment (leakage coil, arrester, ground blade) can also be placed in the secondary terminal box.
Main technical and metrological characteristics
| Characteristics | VCU-123 | VCU-170 | VCU-245 | VCU-362 | VCU-525 | VCU-765 |
| Highest operating voltage, kV | 126 | 170 | 252 | 363 | 525 | 787 |
| Voltage class, kV | 110 | 170 | 220 | 330 | 500 | 750 |
| Rated voltage of the primary winding, kV | 110/√3 | 170/√4 | 220/√3 | 330/√3 | 500/√3 | 750/√3 |
| Rated voltage of the main secondary windings, V | 100 /√3 or 110 /√3; | |||||
| Rated voltage of additional secondary winding, V | 100 or 110 or 100 / 3 or 110 / 3 | |||||
| Number of secondary windings: main | 1 or 2 | |||||
| additional | 1 | |||||
| Accuracy class of the main secondary winding for measurements / | in accuracy class 0.2 | in accuracy class 0.5 | in accuracy class 1.0 | |||
| Rated load a1 – x1 | 50 or 100 or 200 VA | 50 or 100 or 200 VA | 100 or 200 or 300 VA | |||
| Winding accuracy class for protection / Nom. Load ad - xd | in accuracy class 3P 100 or 200 or 400 or 600 VA | |||||
| Winding accuracy class for electricity metering / Nom. load a2 – x2 | in accuracy class 0.2 30 or 50 or 100 VA or 200 VA | |||||
| Permissible total load for the main windings while maintaining the required accuracy classes 0.2: 200 VA | ||||||
| Rated frequency, Hz | 50 | |||||
| Operating temperature range, ˚С | from -60; -45; -35 to +40 | |||||
| Temperature range during transportation, ˚С | from -45 to +50 | |||||
Standard overall and installation dimensions
| Type | Voltage class | Nom. capacity | Transformer height | Transformer weight | Oil mass (IU+EMU) | Fixing dimensions | Ud. creepage distance min. |
| kV | pF | mm | kg | kg | mm | mm | |
| VCU-123 | 110 | 8800 | 1800 | 315 | 10+40 | 470x470 | 3075 |
| 14700 | 1850 | 335 | 15+40 | 470x470 | 3075 | ||
| VCU-170 | 170 | 6300 | 2270 | 350 | 14+40 | 470x470 | 4250 |
| VCU-245 | 220 | 4400 | 3045 | 440 | 20+40 | 470x470 | 6125 |
| 7400 | 3165 | 480 | 30+40 | 470x470 | 6125 | ||
| VCU-362 | 330 | 5300 | 3920 | 550 | 42+40 | 470x470 | 9050 |
| 7000 | 3925 | 610 | 55+40 | 470x470 | 9050 | ||
| VCU-525 | 500 | 3500 | 5370 | 735 | 60+40 | 470x470 | 11820 |
| 4650 | 5370 | 755 | 75+40 | 470x470 | 11820 | ||
| 6000 | 5370 | 860 | 98+40 | 470x470 | 11820 | ||
| VCU-765 | 750 | 3000 | 6485 | 1110 | 105+60 | 530x530 | 17710 |
The stated values refer to our standard versions of capacitive transformers with porcelain insulators.
Transformers with other values are available on request. The final dimensions and weights of transformers depend on the specific electrical, mechanical and environmental characteristics specified in the customer's request.
