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MT/T 661-2011 PDF in English


MT/T 661-2011 (MT/T661-2011, MTT 661-2011, MTT661-2011)
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MT/T 661-2011: PDF in English (MTT 661-2011)

MT/T 661-2011
MT
COAL INDUSTRY STANDARD OF
THE PEOPLE’S REPUBLIC OF CHINA
ICS 73.100.99
D 98
Registration number. 31797-2011
Replacing MT/T 661-1997
General technical condition for electrical
apparatus used underground mine
ISSUED ON. APRIL 12, 2011
IMPLEMENTED ON. SEPTEMBER 01, 2011
Issued by. State Administration of Production Safety
Table of Contents
Foreword ... 3 
1 Scope ... 5 
2 Normative references ... 5 
3 Classification ... 7 
4 General requirements ... 7 
5 Technical requirements ... 9 
6 Test methods ... 27 
7 Inspection... 30 
8 Marking, packaging, transport and storage ... 31 
Appendix A (Normative) Classification of electrical apparatus for underground
coal mine ... 33 
Appendix B (Normative) Main inspection items for electrical apparatus used in
underground coal mines ... 36 
Appendix C (Normative) Standard clauses of the corresponding provisions cited
in various inspection items for electrical apparatus used in underground coal
mines ... 38 
Foreword
This standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This standard is a revision of MT/T 661-1997 “General technical condition for
electrical apparatus used underground mine”.
From the date of implementation of this standard, MT/T 661-1997 “General
technical condition for electrical apparatus used underground mine” is
abolished.
As compared with MT/T 661-1997, the main changes in this standard are as
follows.
- DELETE the description on the normative references in the foreword (see
the foreword of the 1997 version);
- DELETE the test requirements for transport (see 5.1.9 of the 1997 version);
- MODIFY the classification of electrical apparatus (see Appendix A; clause
3 of the 1997 version);
- ADJUST the structural layout as required for the insulation resistance value
(see Table 11 and Table 12; Table A.1 of the 1997 version);
- MODIFY the provisions for the selection of electrical apparatus for
underground mine;
- MODIFY the electric clearance and creepage distances (see Table 3; Table
5 of the 1997 version);
- MODIFY the tracking resistance of insulating materials (see Table 4; Table
6 of the 1997 version);
- MODIFY the overload protection characteristics of the starter (see Table 17;
Table 7 of 1997 version);
- MODIFY the rated lightning impulse withstanding voltage (see Table 8;
Table 9 of the 1997 version);
- MODIFY the rated short-time power frequency withstanding voltage of high-
voltage electrical apparatus (see Table 10; Table 11 of the 1997 version);
- ADD the color of the main circuit conductor as well as the arrangement of
the phase sequence of the main circuit (see 5.2.16 and 5.2.17);
- ADD the performances of phase failure protection and leakage blocking
protection (see Table 18 and Table 19).
General technical condition for electrical
apparatus used underground mine
1 Scope
This standard specifies the classification, technical requirements, test methods,
inspection rules, marking, packaging, transportation and storage of electrical
apparatus used underground mines.
This standard applies to electrical apparatus used underground mines (referred
to as electrical apparatus).
2 Normative references
The following documents are essential to the application of this document. For
the dated documents, only the versions with the dates indicated are applicable
to this document; for the undated documents, only the latest version (including
all the amendments) are applicable to this standard.
GB/T 156 Standard voltages
GB/T 191 Packaging - Pictorial marking for handling of goods
GB 311.1 Insulation co-ordination for high voltage transmission and
distribution equipment
GB/T 762 Standard current level
GB 1984 High-voltage alternating-current circuit-breakers
GB 1985 High-voltage alternating-current disconnectors and earthing
switches
GB/T 2423.1 Environmental testing for electric and electronic and electronic
products - Part 2. Test methods - Tests A. Cold
GB/T 2423.2 Environmental testing for electric and electronic products - Part
2. Test methods - Tests B. Dry heat
GB/T 3309 Mechanical test at ambient temperature for high-voltage
switchgear
GB 3836.1-2000 Electrical apparatus for explosive gas atmospheres - Part
1. General requirements
GB 3836.2-2000 Electrical apparatus for explosive gas atmospheres - Part
2. Flameproof enclosure d
GB 3836.3 Electrical apparatus for explosive gas atmospheres - Part 3.
Increased safety e
GB 3836.4 Electrical apparatus for explosive gas atmospheres - Part 4.
Intrinsic safety i
GB/T 4026 Basic and safety principles for man-machine interface, marking
and identification - Identification of equipment terminals and terminations of
certain designated conductors, including general rules for an alphanumeric
system
GB 4208 Degrees of protection provided by enclosure (IP code)
GB/T 4728 Graphical symbols for diagrams
GB/T 5094.1 Industrial systems, installations and equipment and industrial
products - Structuring principles and reference designations - Part 1. Basic
rules
GB/T 7159 General rules for the formulation of letter symbols in
electrotechnology
GB/T 11022-1999 Common specifications for high-voltage switchgear and
control-gear standards
GB/T 12173 Mining electrical apparatus for non-hazardous area
GB/T 13384 General specifications for packing of mechanical and electrical
product
GB 14048.1-2006 Low-voltage switchgear and control-gear - Part 1. General
rules
GB 14048.2 Low-voltage switchgear and control-gear - Part 2. Circuit-
breakers
GB 14048.3 Low-voltage switchgear and control-gear - Part 3. S witches
disconnectors switch-disconnectors and fuse-combination units
GB 14048.4-2003 Low-voltage switchgear and control-gear -
Electromechanical contactors and motor-starters
GB/T 14808 High-voltage alternating current contactors and contactor-
4.6 The rated frequency of electrical apparatus is generally 50 Hz.
4.7 Electrical apparatus is generally 8 h working system. The others are
regulated by their respective product standards.
4.8 Electrical apparatus shall be equipped with the necessary spare parts,
accessories, special tools and accompanied files. It shall be provided with two
sets of important electronic plug-in, or one set of general electronic plug-in, to
facilitate the use, management, maintenance of the user. The accompanied
files shall include the product certificate, instructions for use, packing list.
5 Technical requirements
5.1 Conditions for normal use
Electrical apparatus shall work reliably under the following conditions.
a) The ambient air temperature is -5 °C ~ +40 °C1), the average temperature
within 24 h does not exceed 35 °C.
b) Altitude of the location of installation. The altitude of low-voltage electrical
apparatus does not exceed 2000 m 2 ). The altitude of high-voltage
electrical apparatus does not exceed 1000 m3).
c) Relative humidity of the surrounding air. The relative humidity of the air
does not exceed 50% at a maximum temperature of 40 °C. It allows a
higher relative humidity at a lower temperature, for example, 90% at 20 °C.
For the condensation that occasionally occurs due to temperature
changes, it shall take special measures.
d) The use in places where there is a risk of gas and coal dust explosion
shall follow the provisions of clause 4.3.
e) In a non-corrosive, non-insulation-destructive gas or vapor environment.
f) In places where there is no significant vibration or shock.
g) In places where dripping and liquid intrusion are prevented.
h) The grade of contamination is grade 3.
5.2 Requirements for structure and explosion-proof
1 For the use of electrical apparatus when the ambient air temperature is above +40 °C or below -5 °C,
refer to the notes to clause 6.1.1 of GB 14048.1-2006.
2 For the low-voltage electrical apparatus which is installed at an altitude of more than 2000 m, refer to
the provisions of note 6.1.2 of GB 14048.1-2006.
3 For the high-voltage electrical apparatus which is installed at an altitude higher than 1000 m, follow the
provisions of clause 2.2.1 of GB/T 11022-1999 to convert the relevant parameters.
5.2.5 Markings, interlocks and warning labels
5.2.5.1 On the obvious parts of the enclosure of electrical apparatus, it shall
provide a clear and durable marking. The marking for the explosion-proof
electrical apparatus shall comply with the provisions of clause 27 of GB 3836.1-
2000. The marking of common type electrical apparatus for mining use shall
comply with the relevant provisions of GB/T 12173.
5.2.5.2 The interlocking device of electrical apparatus shall comply with the
provisions of clause 10 of GB 3836.1-2000.
5.2.5.3 For the electrical apparatus that generates sparks or arcs during normal
operation, its enclosure which uses the quick-acting door cover shall be
provided with an interlocking device. When the power is turned on, the
enclosure’s door cannot be opened; when the enclosure’s door cover is opened,
the power cannot be turned on. The door cover which is fixed by the use of bolts
is allowed to use the warning label, on which it shall indicate the words “It is
forbidden to open the cover with power”.
5.2.5.4 For the electrical apparatus which has a DC voltage higher than 60 V
and the AC voltage higher than 36 V, if the live part may be accessed after
opening the cover or removing the apparatus’s parts, it shall provide the
protective cover which has a degree of protection not less than IP20, as well as
the warning labels of “Beware of electric shock” or “Electricity”.
5.2.5.5 For the structures which are interlocked by the use of isolation switch, it
shall be clearly visible at the opening position of the contact, or otherwise it shall
be able to correctly judge the contact’s status through the position of handle.
5.2.5.6 For the enclosure of electrical apparatus with built-in capacitors, heat
elements and quick-acting door or cover structure, the time interval from power-
off to opening of cover shall comply with the provisions on the allowable time
for opening the door or cover of enclosure in GB 3836.1-2000. It shall provide
the warning label on the time interval. The time interval shall be as specified by
the product standards.
5.2.6 Structures of cable and conduit entry device
The cable and conduit entry device shall be selected according to different
structural types. The common type for mining use shall comply with the
provisions on the cable entry device of GB/T 12173. The cable and conduit
entry device of explosion-proof type (except for intrinsic safety type) shall
comply with the provisions of clause 16 of GB 3836.1-2000. The introduction
and connection of flameproof cables and conductors shall also comply with the
provisions of clause 12 of GB 3836.2-2000.
5.2.7 Electrical clearance and creepage distance
Flameproof electrical apparatus for mining use shall comply with the relevant
provisions of GB 3836.1-2000, in addition to the provisions of GB 3836.2-2000.
5.2.12 Increased safety electrical apparatus for mining use
The electrical apparatus which is used in the shaft station of underground coal
mine, trunk intake airway, main intake airway, and other places (see Table 1)
may be of increased safety type. The marking is “Exe I”.
The increased safety electrical apparatus for mining use shall, in addition to
complying with the provisions of GB 3836.3, also comply with the relevant
provisions of GB 3836.1-2000.
5.2.13 Intrinsic safe electrical apparatus for mining use
Electrical apparatus which is used in underground coal mine where there is gas
or coal dust explosion hazard may be of intrinsic safe type. The marking is “Exib
I” or “Exia I”.
The intrinsic safe electrical apparatus as well as its related equipment shall, in
addition to complying with the provisions of GB 3836.4, also comply with the
relevant provisions of GB 3836.1-2000.
5.2.14 Composite type electrical equipment
If more than one explosion-proof types are used on an electrical apparatus, it
shall first indicate the markings of the primary explosion-proof type, followed by
the markings of the other explosion-proof types. The method of marking is as
shown in the relevant provisions of GB 3836.1-2000. For example, the
explosion-proof marking for the flameproof-and-intrinsic-safe combined
electrical apparatus is “Exd[ib] I”.
The composite type electrical apparatus shall, in addition to the special
standards for the relevant explosion-proof type, also comply with the provisions
of GB 3836.1-2000.
5.2.15 Graphic symbol of electrical schematic diagram
Electrical apparatus’s enclosure shall generally have electrical schematic
diagrams or wiring diagram label. The graphic symbols and wiring numbers as
indicated in the drawings shall comply with the provisions of such standards as
GB/T 4026, GB/T 4728, GB/T 5094.1, GB/T 7159.
5.2.16 Color of conductors
5.2.16.1 If the busbar of the main circuit and the insulation conductors of the
electrical apparatus are marked by color, it may make reference to the
provisions of Table 5. Meanwhile it shall also consider its mechanical strength
5.6, 5.7, 5.8 of GB/T 11022-1999. It shall also meet the following requirements.
For the control devices such as low-voltage starters and contactors, when using
electromagnetic operation, within the range of ambient air temperature -5 °C ~
+40 °C, at the control power supply’s voltage within the range of 75% ~ 110%
of the rated voltage (Us), or within the range of 85% ~ 110%, it shall pull-in
reliably. At this time, the value of 75 % or 85% indicates the lower limit of the
pull-in action voltage, whilst the value of 110% shall be the upper limit. This
action range is applicable to AC and DC.
Note. Whether the fluctuation range of the control power supply’s voltage is 75%
~ 110%, or 85% ~ 110% is determined by the product standard or the
manufacturer.
The release voltage during electromagnetic operation shall not be higher than
60% of the rated control power supply’s voltage (Us). The release voltage shall
not be less than 20%Us for AC frequency; it shall not be lower than 10%Us for
DC.
For the high-voltage contactors, starters and other control apparatus, when
using electromagnetic operation, within the range of ambient air temperature -
5 °C ~ +40 °C, at the control power supply’s voltage within the range of 85% ~
110% of the rated voltage (Us), it shall pull-in reliably. At this time, the value of
85% indicates the lower limit of the pull-in action voltage, whilst the value of
110% shall be the upper limit. This action range is applicable to AC and DC.
For lock-type appliances, the limit value of the pull-in action shall be negotiated
between the supplier and the purchaser.
The shunt trip device, undervoltage trip device and overcurrent trip device of
high-voltage and low-voltage distribution appliances shall comply with the
provisions of GB 14048.1-2006 regarding the operating range of undervoltage
relays and trip device. The range of the action of the shunt trip device, the
current action relay and the trip device shall also comply with the provisions of
GB 1984 regarding the closing operation and tripping operation.
The operating conditions of high-voltage and low-voltage distribution electrical
appliances shall comply with the relevant operating conditions in GB 14048.2,
the relevant operating mechanism in GB 1984, the relevant clauses on
operating mechanisms in GB 1985.
5.3.2 Temperature-rise
The temperature-rise of such parts as the wiring terminals, accessible parts,
main circuits, control circuits, auxiliary circuits of such control appliances as
low-voltage starters, contactors, feed switches, etc. shall comply with the
provisions on temperature-rise in GB 14048.1-2006, GB 14048.2, GB 14048.4-
interlocks and/or electrical interlocks which are installed under normal status
shall be used.
5.3.4.4 Dual-speed starter
The switch-on and switch-off capability of the dual-speed starter is same as that
of the common starter. The product shall have the automatic or manual
switchover device or function from low-speed to high-speed. The switching can
be based on the time principle and current principle. The switching time and
current are as specified by the product standard or by the user and the
manufacturer through negotiation.
5.3.4.5 Overload current withstanding capability
For the contactors which use the category AC-3, AC-4, the overload current
withstanding capability of the starter shall comply with the requirements for the
overload current withstanding capability in GB 14048.4-2003.
5.3.4.6 Agreed operational performance
The low-voltage switchgear shall comply with the provisions of the agreed
operational performance in GB 14048.1-2006;
The high-voltage switchgear shall comply with the relevant provisions on
mechanical operational performance of the isolating appliance in GB 1984, GB
1985, GB/T 11022-1999, as well as the supplementary provisions as follows.
Operational control power supply’s voltage for the agreed operational
performance of contactors and starters follows the operating conditions as
specified in this standard. The switch-on and switch-off conditions for the
operation of different categories of use shall comply with the provisions of the
agreed operational performance in GB 14048.4-2003.
5.3.4.7 Mechanical life (mechanical durability)
The mechanical life of low-voltage switchgear shall comply with the provisions
of GB 14048.1-2006, GB 14048.2, GB 14048.3, GB 14048.4-2003. The number
of mechanical life test is recommended as.
0.1, 0.3, 1, 3, 6, 10, 30, 100 (10000 times).
It is specifically specified by product standards.
The mechanical life of high-voltage switchgear shall meet the requirements of
mechanical life clauses in GB 1984, GB 1985, GB/T 11022-1999, JB 8739.
5.3.4.8 Electrical life (electrical durability)
voltage distribution device adopts the protection principle of power direction
type, current type or current direction type, the action parameters of the single-
phase grounding protection device are specified as follows.
- The primary lowest starting current of zero sequence current transformer I0
= 0.5 A; the maximum setting current I0 = 6 A;
- The minimum starting voltage of the opening voltage of the open delta of
the voltage transformer U0 = 3 V; the maximum setting voltage U0 = 25 V.
The leakage resistance shall reliably act at 1 kΩ. The U0 action value is
recommended not to exceed 10 V. The recommended maximum value of the
setting current Ie is not more than 2 A, to improve the sensitivity of the leakage
protection device. The action time of the protection device itself is ≤ 100 ms.
In addition to the above protection, the rest is as specified by product standards.
Note. According to the need, the user negotiates with the manufacturer to
determine what kind of protection is set. The specific technical parameters of
the above protection are as specified by the product standard according to the
relevant standards, in addition to the provisions of GB 14048.4-2003 and this
standard.
5.3.8 Requirements for electromagnetic compatibility (EMC)
Unless otherwise specified in the product standards, the electromagnetic
compatibility of electrical apparatus shall meet the requirements for
electromagnetic compatibility (EMC) in GB 14048.1-2006 and GB/T 11022-
1999.
5.4 Environmental requirements
5.4.1 Alternated damp heat test
The common type electrical apparatus for mining use shall meet the
requirements for the damp heat test in GB/T 12173. The severity of the
alternated damp heat test is as follows. the high-temperature is 40 °C. Test
period. 6 d for instruments and meters, 12 d for low-voltage electrical apparatus,
21 d for high-voltage electrical apparatus. After the test, it shall assess the
electrical insulation properties of the test specimens.
Explosion-proof electrical apparatus shall comply with the provisions of
Appendix C of GB 3836.1-2000. The severity of the alternated damp heat test
is as follows. the high-temperature is 40 °C. Test period. 6 d for the intrinsic safe
portable instruments and meters; 12 d for the low-voltage electrical apparatus;
21 d for high-voltage electrical apparatus. After the test, it shall assess the
electrical insulation properties of the test specimens.
clauses as cited in each test are respectively as shown in Table B.1 of Appendix
B, Table C.1 of Appendix C.
For the electrical apparatus, it shall, based on their characteristics, this standard,
the provisions of relevant product standards, determine the test item or test
sequence in the product standard. Unless otherwise specified, the number of
test samples for each test shall be not less than 2.
7.1.3 Exit-factory inspection
The exit-factory inspection is to check the defects of the material and
processing of the product. It is the inspection and test item that the
manufacturer shall carry out before exit-factory.
The exit-factory inspection & test items and the corresponding standard
provisions as cited by each test item are respectively as shown in Table B.1 of
Appendix B and Table C.1 of Appendix C in this standard.
7.2 Inspection rules
7.2.1 Inspection rules for type inspection
The electrical apparatus used for type inspection shall be a sample which
complies with the design requirements in terms of structure, manufacture,
material, etc., and pass the exit-factory inspection. If all test items (or
sequences) of the type inspection can pass the test and all the samples
subjected to the test are qualified, it can be deemed that the type inspection of
this electrical apparatus is qualified. Otherwise, it shall analyze the causes, take
measures, even improve design, workmanship, tooling, etc., until the type
inspection is qualified.
If the tested sample in the type inspection has the defects which does neither
pose a threat to safety neither reduce the main performance, meanwhile the
manufacturer provides sufficient evidence to prove that such defects are not
inherent in the design but caused by individual samples, it allows for
reinspection. The product standard shall specify the test item, quantity, and
qualification criteria which allow for reinspection.
7.2.2 Inspection rules for exit-factory inspection
The exit-factory inspection items shall be carried out one by one on each exit-
factory product. The unqualified products shall be reworked or repaired one by
one until they are fully qualified. If it cannot be repaired, it shall be scrapped.
8 Marking, packaging, transport and storage
8.1 Marking
Appendix A
(Normative)
Classification of electrical apparatus for underground coal mine
A.1 Classification by rated voltage of electrical apparatus
a) Low-voltage electrical appliances for mining use which has a rated voltage
lower than or equal to 1200 V (referred to as low-voltage electrical
appliances).
b) High-voltage electrical appliances for mining use which has a rated
voltage greater than 1200 V (referred to as high-voltage electrical
appliances).
A.2 Classification by type of electrical apparatus
a) Common electrical apparatus for mining use (referred to as the common
type “KY”).
b) Explosion-proof electrical apparatus for mining use (referred to as
explosion-proof type).
1) Flameproof electrical apparatus (referred to as flameproof type “Exd l”);
2) Increased safety electrical apparatus (referred to as “Exe l”);
3) Intrinsic safe circuits and electrical apparatus (referred to as intrinsic
safe type “Exib I, Exia I”);
4) Positive-pressure type electrical apparatus (referred to as positive-
pressure enclosure type “Exp I”);
5) Oil-immersed electrical apparatus (referred to as oil-immersed type
“Exo I”);
6) Sand-filled electrical apparatus (referred to as sand-filled type “Exq I”);
7) Encapsulated electrical apparatus (referred to as encapsulated type
“Exm I”);
8) Special electrical apparatus (referred to as encapsulated type
[translator’s note. should be special type] “Exs I”);
9) Composite electrical apparatus (e.g., flameproof and intrinsic safe
composite type “Exd[ib] I”).
d) Auxiliary and others.
1) Flameproof low-voltage resistance box;
2) Flameproof low-voltage electromagnet;
3) Flameproof low-voltage meter box;
4) Flameproof low-voltage junction box;
5) Flameproof low-voltage latch;
6) Explosion-proof integrated protection device for the transformer of
electric coal drill;
7) Flameproof integrated protection device for lighting transformer;
8) Flameproof low-voltage leakage detection relay;
9) Flameproof high-voltage cable connector;
10) Flameproof high-voltage junction box;
11) Increased safety type low-voltage cable junction box;
12) Increased safety type high-voltage cable junction box;
13) Intrinsic safe junction box.
A.4 Classification by the operation method of electrical apparatus
a) Manual operation;
b) Energy storage operation;
c) Power operation.
A.5 Classification by arc extinguishing media of electrical apparatus
a) Air;
b) Vacuum;
c) Contactless.
......
 
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