TYPICAL SOURCE OF EMERGENCY POWER IN CARGO SHIPS
WHAT DOES SOLAS SAY?
– The emergency source of electrical power may be either a generator or an accumulator battery, which shall comply with the following:
– Where the emergency source of electrical power is a generator, it shall be:
- Driven by a suitable prime mover with an independent supply of fuel having a flashpoint (closed cup test) of not less than 430C;
- started automatically upon failure of the electrical supply from the main source of electrical power and shall be automatically connected to the emergency switchboard; those services which are covered by transitional source of power shall then be transferred automatically to the emergency generating set.
- The automatic starting system and the characteristic of the prime mover shall be such as to permit the emergency generator to carry its full rated load as quickly as is safe and practicable, subject to a maximum of 45 s; unless a second independent means of starting the emergency generating set is provided, the single source of stored energy shall be protected to prevent its complete depletion by the automatic starting system; and provided with a transitional source of emergency electrical power.
– Where the emergency source of electrical power is an accumulator battery, it shall be capable of:
- carrying the emergency electrical load without recharging while maintaining the voltage of the battery throughout the discharge period within 12% above or below its nominal voltage;
- Automatically connecting to the emergency switchboard in the event of failure of the main source of electrical power; and immediately supplying at least those services specified.
Location: “The emergency source of electrical power, associated transforming equipment, transitional source of emergency power, emergency switch board and emergency lighting switch board” Shall be located above the uppermost continuous deck and shall be readily accessible from the open deck.
- They shall not be located forward of the collision bulk head (Administration may permit in exceptional circumstances)
- shall be located in such a way that a fire (or) other casualty in the space containing main source of electrical power and its associated equipments (or) fire / other casualty in a category A machinery space will not interfere with the supply, control and distribution of
- The space containing emergency source of electrical power and its associated equipments shall not be contiguous to the boundaries of the machinery spaces of Category A.
Where the emergency source of electrical power is accumulator battery, it shall be capable of:
- The emergency switchboard shall be installed as near as is practicable to the emergency source of electrical power.
- The emergency switchboard shall be supplied during normal operation from the main switchboard by an interconnector feeder which is to be adequately protected at main switchboard against overload and shot circuit and which is to be disconnected automatically at the emergency switchboard upon failure of main source of electrical power.
- If the system is arranged for feedback operation, the interconnector feeder is also to be protected at the emergency switchboard at least again short circuit.
- There shall be a provision made for periodic testing of the computer emergency system and shall include the testing of automatic starting arrangements.
- The emergency generator and its primary move/ any emergency accumulator battery shall be so designed to operate at full rated power when the ship is up righted & when inclined at any angle of list up to 22.5° or when inclined up to 10° either in fore & aft direction or is in any combination of angle within those limits.
Typical list of essential services, which must be supplied simultaneously.
The emergency sources of electrical power shall supply to emergency lighting; for a period of 18 hours to the following:
1) Accommodation, alleyways, stairs, exits, lifts and lifts trunks.
2) In machinery spaces and main generating stations
3) ECR, CCR, main and emergency switchboards
4) Fire control stations, at S/G, at fire pumps, sprinkler pumps, etc.
5) Cargo pump rooms
This list may extend depending upon the administration
For 18 hours
1) Navigation lights
2) VHF radio installations
3) MF radio installations
4) HF radio installations
5) All internal communication equipment
6) Navigational equipment
7) Fire detection and fire alarm systems
8) One of the main fire pumps if dependent upon emergency generator.
If the ship is engaged in voyages of short duration regularly, the administration if satisfied, it may be reduced from 8 hours period but not less than 12 hours.
PERIODICAL TESTING OF THE EMERGENCY INSTALLATION:
* Correct functioning of the auto start equipment is obliviously vital to the production of emergency power. Regular, weekly, testing of the emergency generator should include simulation of the loss of normal power. The start-up equipment may provide a pushbutton to interrupt the normal voltage supply to the panel which then triggers the start sequence.
* Loss main power supply can easily be simulated by pulling a fuse in the auto start pane which supplies the under – voltage or under frequency relay.
* Emergency generators should be regularly checked and run up to speed for short test runs to comply with safety regulations. These no load running checks should when practicable, be supplemented occasionally by a proper load test.
* This requires the disconnection of normal mains power while the emergency generator is loaded up to near its rated value. Only the proper load test will prove the performance of the generator and its prime mover, together with its circuit breaker operation.