HV Switchgear Switching System

Abstract

HV switchgears are normally well built and accidents are rare but when they do happen, the consequence to human life, downtime, financial losses and image of the company and stakeholders can be very significant. Therefore, it is always best to perform any HV switching from a safe distance away. Statistically, accidents are caused by human or mechanical issues which creeps up over time. In this work, after much deliberation an electropneumatic system was developed to trigger HV switching from 25 m away. Much trial and error were done to achieve the finalized system The Switchgear Safety System developed was tested to be capable of switching a 11kV OCB, the racking in and out of the cubicle type VCB and even replacing the human finger to push the push-button type of motorized HV switchgears which is commonly sold today. Though these latest push-button type switchgears look safe, only the high muscular strength human hand action is replaced by an electric motor, the mechanical engineering system behind, is still the same and therefore should be switched from a safe distance away.

A System to Ensure Safety while Switching High Voltage Switchgears

“…This means the breaking is 2.58 times more dangerous than the making [12]. The material used to blow onto the arc can also be ionized because exerting an arc onto a material is the method of converting atoms to ions [14]. For example, ionizers which are sold in markets or especially within refrigerators to preserve vegetables basically use the principle of pushing air over an arc.…”

“…In the Sarawak grid as in most other grids, only 11kV switchgears are operated manually, 33kV, 132kV 275kV switchgears are normally remotely operated from the State Control Centre (SDC) of the Local Electrical Authority (LEA) [2].…”

“…It must be noted that it takes a very strong person to pull the Lucy brand switchgears. During the initial test a 4mm 2 cable was used to fasten the pneumatic cylinder to the switchgear handle. Tight triple knots were made but the force was so strong that the knots came loose.…”

“…The latest HV switchgears are designed such that a small push button will trigger a motor to actuate the switchgear. Though this setup looks neat and safe, the danger from improper mechanical actuation from things like an insufficiently greased shaft can still cause a large arc that can easily pierce through the 2-3mm cubicle switchgear body, resulting in fatality [6]; [7]. Therefore, the finger pushing in front of a cubicle switchgear needs to be replaced by an actuator performing it and the human triggering it from up to 25m away.…”

Proving that Eddy Current is the Main Heat Generator for a Current Carrying Cable Suspended in a Steel Pipe

“…The N2 is to displace the O2 and thus prevent corrosion of the transmission cable. But since the pipes are expensive, it was proposed that a pump be placed to compress the N2 to double the pressure such that a 4" Ø pipe can be used to bring the N2 back to Kuching to be cooled before sending it back in the 8" Ø pipe to Pengerang [5].…”