Fuse handcarts, voltage transformer handcarts, isolation handcarts, grounding handcarts and voltage test handcarts are common functional handcarts in high-voltage switchgear (such as KYN, center cabinet, etc.). They have their own functions in the power system, and they are both related and different. The following is a detailed comparison of them:
1. Fuse Cart
Function:
Integrated high-voltage fuses (such as current-limiting fuses) to protect circuits from overload or short-circuit currents, usually used in conjunction with load switches.
Features:
Simple structure, low cost, but the fuse needs to be replaced after it blows.
Commonly used in voltage transformer protection or small-capacity transformer protection circuits.
Application scenarios:
Used in situations where fault currents need to be cut off quickly but do not require frequent operation.
2. Voltage transformer handcart (PT handcart)
Function:
Install voltage transformer (PT) to convert high voltage to low voltage (such as 10kV→100V) for measurement, protection or metering.
Features:
Usually with fuse protection (such as RN2 type).
Can be pulled out with power on for easy maintenance.
Application scenario:
In switch cabinets where bus voltage needs to be monitored.
3. Isolation handcart (isolating switch handcart)
Function:
Used for electrical isolation to ensure that the circuit has a clear disconnection point during maintenance, but it does not have the ability to disconnect load current or fault current.
Features:
No arc extinguishing device, must be operated under no load.
Simple structure, only physical isolation is provided.
Application scenario:
Maintenance or segmented busbar occasions where power supply isolation is required.
4. Grounding handcart (grounding switch handcart)
Function:
Ground the circuit to ensure the safety of maintenance personnel and prevent wrong power supply.
Features:
Divided into working grounding (manual closing during maintenance) and fast grounding (automatic closing in case of fault).
Usually interlocked with isolation trolley to avoid live grounding.
Application scenario:
Ground the busbar or cable before equipment maintenance.
5. Electricity tester handcart (electricity tester handcart)
Function:
Detect whether the circuit is energized to ensure safe operation.
Features:
Integrated high-voltage electrician (such as sound and light alarm).
Electricity test is required before operating the grounding handcart.
Application scenario:
Confirm that there is no voltage in the circuit before maintenance.
summary
| Handcart type | Core function | Can it break the current | Operation conditions | Typical interlocking relationship |
|---|---|---|---|---|
| Fuse handcart | Overload/short circuit protection | Yes (through fuse) | Automatically operate in case of fault | Used with load switch |
| Voltage transformer handcart | Voltage conversion and measurement | No | Live operation | Usually equipped with fuse protection |
| Isolation handcart | Electrical isolation | No (no arc extinguishing capability) | No-load operation | Interlock with circuit breaker and grounding switch |
| Grounding handcart | Safety grounding | No (closed ground only) | No-voltage operation | Must be interlocked with isolation handcart |
| Electricity test handcart | Detection voltage | No | Live detection | Electricity must be tested before operation |
Key points of difference
Functional differences:
Fuse trolleys are used for protection, PT trolleys are used for measurement, and isolation/grounding/electricity test trolleys are used for safe operation.
Operational capability:
Only fuse trolleys can actively break current, and the other trolleys do not have the breaking capability (isolation trolleys need to be operated without load).
Safety interlock:
Grounding trolleys and isolation trolleys are usually interlocked with circuit breakers to prevent misoperation; the electric test trolley is a prerequisite for grounding operation.
Contact us
If you need further technical support or product selection advice, please provide your specific needs and we will serve you as soon as possible!
email:pannie@hdswitchgear.com.
