Case studies
Specifications
: 7,2 kV; 200 A; 20 kA /1s
Delivery date
: 11.03.2019
Destination
: Česká republika
I want similar solution
Challenge
At a cement plant in the Czech Republic, eight cement mills equipped with medium-voltage motors are installed and must be shut down approximately five times per month for cleaning of technological components. These interventions do not involve electrical equipment; however, without an appropriate technical solution they would require the presence of an electrician during every service operation.
The customer’s objective was to create a system that would allow safe disconnection of the MV motor directly at the point of the technology, enabling maintenance technicians to work independently, without risk and without intervention in the electrical system beyond a clearly defined procedure.
Our Solution
IVEP designed and delivered an indoor MV switchgear of type MSVI, intended for installation in close proximity to MV motors and adapted to the dusty environment of a cement plant.
The core principle of the solution is a strictly defined sequence of operations linking the upstream substation, the control system, and the local disconnector at the motor.
Technical Specifications
- Rated voltage: 7.2 kV
- Rated current: 200 A
- Short-circuit withstand: 20 kA / 1 s
Safe Disconnection Logic
- From the control room, the respective motor is switched off in the upstream substation using the power circuit breaker.
- The cable disconnector is opened and the motor cable is short-circuited.
- The status of individual components is indicated locally at the motor by indicator lights on a mimic diagram (e.g. “operation permitted”).
- Only after this sequence is completed is access to the operating mechanism of the motor-side disconnector released – if required, via a locking solenoid.
- The maintenance technician manually opens the disconnector, secures it with a lock against re-energization, and performs service work on the mill.
Return to Operation
After maintenance is completed, the technician:
- unlocks and closes the local disconnector,
- mechanically secures its position,
- informs the control room that the work has been completed.
Subsequently, from the control room:
- the cable short-circuit is removed,
- the cable disconnector is closed,
- and the mill is returned to operation via the power circuit breaker.
The status of the disconnector at the MV motor is continuously displayed both in the upstream substation and in the control system.
Result
- Safe servicing of cement mills without the need for an electrician’s presence.
- A clearly defined and technically enforced sequence of operations.
- Minimized risk of operational errors in a dusty industrial environment.
- The equipment was delivered on March 11, 2019 and successfully integrated into the cement plant operation.
IVEP Value
This project demonstrates that IVEP addresses not only hardware, but the entire operational process. The combination of mechanical interlocks, signaling, and integration with the upstream system made it possible to create a solution that increases safety, simplifies maintenance, and reduces the customer’s operating costs.