High Voltage Safety. General Safety Instructions for High Voltage Machines. W. Maes. Department of Marine Engineering Antwerp Maritime Academy

Transcription

1 W. Maes Department of Marine Engineering Antwerp Maritime Academy HV, 2015 Outline 1

2 Electric machines have dangerous live and rotating parts and may have hot surfaces. All operations serving, transport, installation, connection, commissioning, operation and maintenance shall be carried out by responsible skilled people Figure : De-energize

3 Figure : Isolate the circuit from the power source Figure : Provide safeguard against reclosing

4 Figure : Connect to earth and short Before starting with the job: The following rules must be strictly applied: De-energize Verify safe isolation from supply Provide safeguard against reclosing Connect to earth and short Cover or provide barriers against neighbouring live parts

5 De-energize auxiliary circuits (for example space heaters)! Note rating plate markings and connection diagram in the terminal box! Figure : safe and permanent electric connection??

6 Figure : always use cablelugs on flexible cable The connection must be made in a way that a safe and permanent electric connection can be maintained Use appropriate cable terminals Establish and maintain safe equipotential bonding

7 Figure : Establish and maintain safe equipotential bonding Figure : Air clearance for HV (IACS)

8 Figure : creepage distances (IACS) The clearances between High Voltage unisolated live parts and between such parts and earth must not be below the values of appropriate standards (minimal) and values given in the manufacturer s documentation No foreign bodies, dirt or moisture is allowed in the terminal box Close unused cable entrance holes and the box itself in a dust- and watertight manner.(maintain its IP rating) Lock the key when the machine is run without coupling

9 Figure : Lock the key when the machine is run without coupling Operation - Safety Rules In case of deviations from normal operation, for example, elevated temperture, noises, vibrations - disconnect machine, if in doubt Establish cause and consult manufacturer, if necessary. Do not defeat protective devices, not even in trial run. In case of heavy dirt deposits, clean cooling system at regular intervals. Open blocked condensate drain holes from time to time.

10 Additional Safety Instructions for Permanent Magnet Synchronous Machines Additional Safety Instructions for Permanent Magnet Synchronous Machines only qualified personnel familiar with the relevant safety requirements are allowed to open and maintain permanent magnet synchronous machines. it is not allowed to remove the rotor of a permanent magnet synchronous machine without the special tools designed for this purpose when the machine s shaft is rotating, a permanent magnet synchronous machine induces a voltage in its terminals the induced voltage is proportional to the rotational speed, and can be hazardous even at low speeds prevent any rotation of the shaft before opening the terminal box and or before working at unprotected terminals

11 Additional Safety Instructions for Permanent Magnet Synchronous Machines the terminals of a machine with frequency converter supply may be energized even when the machine is at standstill beware of revers power when working at the supply system do not exceed the maximum allowed speed of the machine see product specific manuals magnitic stray fields, caused by an open or disassembled permanent magnet synchronous machine or by a seperate rotor of such a machine, may disturb or damage other electrical or electromagnetic equipment, such as cardiac pacemakers, creditcards and equivalent Additional Safety Instructions for Permanent Magnet Synchronous Machines loose metallic parts and wast must be prevented from entering the interior of the permanent magnet synchronous machine as well as getting in contact with the rotor before closing an opened permanent magnet synchronous machine, wast and any parts not belonging to the machine must be removed Beware of magnetic stray fields and possible induced voltages when rotating the separate rotor of a permanent magnet synchronous machine as they may cause damage to surrounding equipment.

12 Rules During any Operation Disconnect and lock out before working on the machine or the driven equipment. Ensure no explosive athmosphere is present while the work is in progress. Rules During any Operation Starting and Restarting Figure : The maximum number of sequential starts...

13 Rules During any Operation Starting and Restarting The maximum number of sequential starts has been declared in machine s technical documents.(ex. autotransformator starting) the new starting sequence is allowed after the machine has cooled down to ambient temperature for a cold start condition or to operating temperature for a warm start condition. Rules During any Operation

14 Rules During any Operation Earthing and Equipotential Bonding Check before starting that all earthing and equipotential bonding cables are effectivly connected. Do not remove any earthing or equipontialing cables, which have been assembled by the manufacturer. Rules During any Operation

15 Rules During any Operation Clearances, creepage and separations Do not make any removal or adjustment in terminal boxes, wich could decrease clearances or creepage distances between parts. Do not install any new equipment to terminal boxes without asking for advise from the manufacturer of the original equipment. Be sure that the air gap between rotor and stator is measured after any maintenance on the rotor or bearings. The air gap shall be the same in any point between the rotor and the stator. Centralize the fan to the centre of the fan hood or the air guide after any maintenance. The clearance shall be at least 1 percent of the maximum diameter of te fan and in accordance with standards. Rules During any Operation Connections in terminal boxes (Ex motors) All connections in main terminal boxes must be made with Ex-approved connectors, wich are delivered with the machine by the manufacturer. All connections, in auxiliary terminal boxes, as marked intrinsically safe circuits (Ex i or EEx i) must be connected to proper safety barriers.

16 For Further Reading I Appendix For Further Reading The Rules Lloyds register of shipping. The Rules ABS.