GB/T 35727-2017 English PDF (GBT35727-2017)

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GB/T 35727-2017: Guideline for standard voltages of medium and low voltage DC distribution system
GB/T 35727-2017
GB
NATIONAL STANDARD OF THE
PEOPLE'S REPUBLIC OF CHINA
ICS 29.020
K 04
Guideline for standard voltages of medium and low voltage
DC distribution system
ISSUED ON: DECEMBER 29, 2017
IMPLEMENTED ON: JULY 1, 2018
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of PRC;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Terms and definitions ... 4
3 General provisions ... 5
4 Medium voltage DC power distribution voltage ... 5
5 Low-voltage DC power distribution voltage ... 6
6 DC voltage deviation ... 7
Appendix A (Informative) Load distance of a DC power distribution system ... 8
References ... 10
Guideline for standard voltages of medium and low voltage
DC distribution system
1 Scope
This standard specifies the voltage levels and voltage deviations that shall be followed
for medium and low-voltage DC power distribution.
This standard applies to the planning, design, construction, and operation of DC power
distribution of ±50 kV and below.
2 Terms and definitions
The following terms and definitions apply to this document.
2.1 DC power distribution system
A power distribution system that exchanges electrical energy with the user's electrical
system in a DC mode.
2.2 nominal system voltage
A given value used to mark or identify the system voltage.
[GB/T 2900.50-2008, definition of 601-01-21]
2.3 DC power supply voltage
The pole-to-pole or pole-to-earth voltage at the supply point of a DC power distribution
system.
2.4 load distance
On the premise of meeting the voltage requirements at the end of the line, the maximum
distance to which unit power can be transmitted, and also can be converted into the
maximum distance to which a certain power can be transmitted.
2.5 DC voltage deviation
The relative deviation of the actual operating voltage from the nominal system voltage.
NOTE: DC voltage deviation is expressed in percentage.
3 General provisions
3.1 The determination of the voltage level of the DC power distribution system shall
adhere to the principles of simplifying the voltage level, reducing the transformation
levels, and optimizing the network structure.
3.2 The determination of the DC distribution voltage level needs to consider the
connection with the existing AC voltage sequence and the convenient access of new
energy, energy storage, DC users, etc.
3.3 The determination of the voltage level of the DC power distribution system requires
comprehensive consideration of the application range, capacity, power supply radius,
voltage deviation, and safety.
3.4 The DC voltage conversion device or AC-DC conversion device included in the DC
power distribution system mainly considers voltage source type.
3.5 The user power supply voltage level shall be determined at the above voltage level
and based on comprehensive consideration of factors such as power capacity,
characteristics of power equipment, power supply reliability, power supply radius,
number of loops of power supply lines, the current status of the local public power grid
and its development plan.
3.6 This standard defines 3000(±1500) V~±50 kV as the medium voltage range, and
110 V~1500(±750) V as the low voltage range.
3.7 This standard specifies the voltage levels of medium and low-voltage public DC
power distribution systems. Special power usage situations can be differentiated
according to actual conditions.
4 Medium voltage DC power distribution voltage
When the nominal DC voltage is in the range of 3(±1.5) kV~±50 kV, the nominal
voltage of the medium voltage DC power distribution system should be selected from
Table 1. Please refer to Appendix A for the load distance of overhead lines in the
medium voltage DC power distribution system.