emergency ventilation system that is controlled from outside and not related to other air ventilation systems.
Emergency ventilation system shall ensure that its air exchanging capacity in 1 hour will be equal to 5 times of the total air volume of the compartment.
(3)Ventilation pipeline
In distribution equipment installation compartments, it is allowed to place continuouswelded pipeline of ventilation system without any hole,ventflange, valve or manhole. It is also permissible to place across these compartments the ventilation pipelines with tight waterproof casing.
Chapter 4-2-3 Workshop Substation
Article 356. Scope
As for the workshop substation installed with full-equipped distribution system, the following requirements shall be satisfied:
(1)Every full-equipped workshop substation should be installed with oil-filled transformers with total capacity not exceeding 3,200kVA.
The oil filled transformers in full equipped substation as well as the transformer in compartments protected by compartment wall shall keep the space, in order to install ventilation system and to facilitate operation.
There is no requirement on the distance between separated rooms of different full-equipped substations or between tight compartments where oil-filled transformer are installed.
(2)Only one full-equipped substation should be installed in the one compartment of workshop substation (it is not allowed to install more than 3 full-equipped stations). The permissible total capacity shall be within 6,500kVA.
Total oil volume of transformers installed in enclosed compartment shall be not over 6.5 tones.
(3)Protective barriers of compartments where full-equipped substations with oil-filled transformer
or tight compartments of oil-filled transformers and oil containing equipment areinstalled with
total oil volume of 60kg or above,shall be made of nonflammable- |
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(4)Total capacity of oil-filled transformers installed on the second floor shall not exceed 1,000kVA. It is forbidden toinstall the oil-filled transformer and full-equipped substation with oil-filled transformer on the third and upper floors.
(5)As for workshop substations and full-equipped substations installed with dry transformer or fireproof insulators, there is no requirement on the limitation of capacity, number of units, distance between them and their locations (on which floor) as well.
Article 357. Workshop Sites
Workshop substation can be installed on the first or second floor of the main or auxiliary manufacture compartments graded level I or II according to fire regulationsmentioned in theVietnam Standard TCVN 2622.
Requirements for installing the workshop substation in dusty or chemically noxious compartments are provided in the Article 360.
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Article 358. Installation of Compartments
When equipment for workshop substation are openly installed in the manufacture compartment, regarding measures for protection against direct contact, protection by enclosure, protective barrier, or placing out of reach is allowed.
When protection by enclosure is used, the degree of protection shall meet the requirements of IP2X in minimum.(see the following figure)
When protection by protective barrier is used, seethe protective barrier clearances of the Article 333 in Technical Regulation.
When protection by placing out of reach is used, see the Article 334 and 339 in Technical Regulation.
Figure 358 Example of protection by enclosure for the conductor of the transformer
Article 359. Oil-collecting Sump
An oil-collecting sump shall be built under transformers and other oil-filled equipment in accordance with the article 353.
Article 360. Ventilation and Fire Prevention Measures of the Transformers Compartment
When installing ventilation system for transformer compartment inworkshop substation with normal surrounding environment, it is allowed to utilize air in the workshop for the ventilation.
In order to ventilate transformer compartment arranged in dusty room where air include conductive or corrosive substances, the ventilation system shall be supplied with outside air or cleanly filtered air.
If the ceiling is made of fireproof materials, it is allowed to directlyexhaust air from transformer compartment to the workshop space.
If the ceiling is made of non-flammable materials, exhaust air from transformer compartment shall be flowed into chimney that is extended at least 1m higher against the roof and accordingthe to following items.
-Ventilation pipe of the transformer compartment adjoined to other house where the walls are fireproof but the roof is made of inflammable materialsshall be installed at least 1.5m far from house walls or separated by a barricade wall that is made of nonflammablematerials and at least
0.6m higher than the roof of the house.
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-It is forbidden toinstall the top opening of the ventilation pipe opposite to the window of the house.
-It is not allowed toinstall the top opening of the ventilation pipe on the wall right under the inflammable lean part of roof or near the air hole on the wall of the adjacent house.
-If there is a window above the door or above the top opening of the ventilation pipe, a protection board jutted out at least 0.7m shall be constructed under such window. The protection board shall
be wider than the window by at least 0.8m at each side of the window.
Regarding full equipped substation installed in separated compartment, ventilation system for its transformers shall comply with requirements in the article 355.
Article 361. Fire Prevention Measures
Compartments where oil-filled transformers or oil circuit breakers are installed shall have doors made of non-flammable materials. And those fire-resistive performances shall be not less than 0.6 hours.
Article 362. Clearance from Passageway
When a substation is placed beside a passageway for transportation, it shall be protected against |
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Full equipped distribution system and substation should be installed in the area awayfrom moving |
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traffic of transportation / lifting means. The passageway width along full equipped distribution |
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equipment and substations as well as passageways along the wall of substations with doors or air |
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equipment, materials, products on the ground, full equipped substation and distribution system should be protected by fence. In such case, protective fence shall be installed to leave a passageway which meets the following items.
The passageway width on which full equipped trolley distribution system and full equipped substation are moved, rotated and operated shall be properly sized.
In case full equipped distribution system and substation are installed in separated compartments, the passageway width is determined as followings:
-Equal to length of trolley of complete distribution equipment plus at least 0.6m if they are arranged in one bank.
-Plus at least 0.8m if they are arranged in two banks.
In any case, the passageway width shall be not less than values specified in the article362 and in partially narrow places in the corridor,the width shall be not less than diagonal dimension of the trolley that may cause obstacle on the movement of trolley.
Passageway width on the back for observation of the full equipped distribution system cubicle and full equipped substation shall be notless than 0.8m. In the narrow point of passageways, the protruding part of equipment shall be within 0.2m.
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compartments of the full equipped distribution system and full equipped substation and in any case, this width shall be not less than 1m.
Article 363. Height of Compartment
Height of the compartment shall be not less than the height of the highest componentsin full equipped distribution system and full-equipped substation added with 0.8m up to the ceiling and 0.3m
up to the beam. Such values can be shortened as long as it still ensures safe and easy implementation
of activities such as replacing, repairing or adjusting the equipment of the distribution system and substation.
Surface of road and floor on which equipment of full-equipped distribution system and full-equipped substation are moved shall be selected based on the maximum loading capacity of the equipments. Doors shall be suitable with dimensions of the equipments.
Chapter 4-2-4 Distribution Equipment and On-Pole Substation
Article 364. Scope
As stipulated in Technical Regulation.
Article 365. As stipulated in Technical Regulation. Configuration of Distribution Equipment and substation on-pole
Distribution equipment configuration or substations are specified in the Technical Regulations. Method of mounting circuit breaker on the pole is shown in the following figure.
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-Roadway side: 4.6m
-Walkway side: 4.0m
Figure 365 (Reference) Japanese installation example of drive engine with lock system of the disconnecting switch in one pole
Article 366. Safety of substation on - pole
As stipulated in Technical Regulation.
Article 367. Minimum clearance from operational floor
As stipulated in Technical Regulation.
Article 368. Placement in an Enclosed Cabinet
As stipulated in Technical Regulation.
Article 369. Connecting Wires
Regarding the protection of wires between the transformer and the panel board and between the panel board and low-voltage overhead lines against mechanical breakdowns, a insulated cable shall be used and this cable should be protected by conduit.
Regarding the material of the conduit, it is preferable to use PVC conduit that have a weather resistant and a self extinguishing performance.
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