1 General provisions
1.0.1 This standard is formulated with a view to making the DC auxiliary power supply system for power engineering meet the requirements of safety, reliability and advanced technology and unify the design principles of DC auxiliary power supply system.
1.0.2 This standard is applicable to the design of DC power supply system for new construction, expansion and reconstruction projects of power plants with a single unit capacity of 1,000 MW and below, substations with a single unit capacity of 1,000 kV and below, series compensation stations and DC converter stations. Power plants include coal-fired power plants, oil-fired power plants, gas-fired power plants and biomass power plants, as well as conventional parts of renewable energy power plants and nuclear power plants. This standard is not applicable to special DC power supply system for communication.
1.0.3 The DC power supply system shall be designed under the principles of safety, applicability, advanced technology, economy and rationality, and the system design shall be as simple and convenient for installation, operation and maintenance as possible.
1.0.4 In addition to this standard, the design of DC auxiliary power supply system shall also comply with the current relevant standards of the nation and industry.
2 Terms
2.0.1
storage battery
two or more battery cells connected electrically as energy sources
2.0.2
vented lead-acid storage battery in fixed location
storage battery consisting of positive plate, negative plate, electrolyte, separator, battery tank, battery cover, acid-proof cap, etc., in which, the space between storage battery tank and the storage battery cover shall be sealed, so as to prevent the gas generated in the storage battery from exhausting from other parts than the acid-proof cap
2.0.3
valve-regulated lead-acid (VR-LA) storage battery
sealed storage battery equipped with a valve allowing gas to escape when the internal pressure of the battery exceeds a predetermined value, that does not need to be supplemented with electrolyte in normal conditions, and that may be classified into the lean liquid type and the colloid type by different electrolytes
2.0.4
nickel-cadmium storage battery
storage battery containing alkaline electrolyte, with nickel oxide in positive electrode and cadmium in negative electrode
2.0.5
DC power supply system
system that supplies DC power in power plants, substations and converter stations and that consists of storage battery, charging equipment, DC power distribution cabinet, feeding network and other DC equipment
2.0.6
floating charge
recharge from the charging device bearing the DC continuous load to storage battery in normal operation to supplement the self-discharge of the battery, so that the battery is in standby at full capacity
2.0.7
equalizing charge
continuous charge to ensure the same charge state of each battery cell in the storage battery, that is, to compensate the voltage imbalance generated in the use of the battery to restore it to the specified range, and recharge after large-capacity discharge
2.0.8
final voltage
lowest discharge voltage that the load of DC power supply system requires the storage battery to maintain in the specified discharge time, in the calculation for storage battery capacity selection, which, for the storage battery itself, refers to the minimum allowable discharge voltage of the storage battery at different discharge rates and conditions within different discharge time
2.0.9
checking discharge
discharge to check the actual capacity of the storage battery in normal operation by discharging at a specified constant discharge current until it reaches the specified final voltage, and calculating the actual capacity of the storage battery based on the discharge current and discharge time
2.0.10
terminal battery
additional battery in the storage battery besides the basic batteries that can meet the system voltage requirements
2.0.11
DC control load
load of electrical and thermal control, signal, measurement and relay protection, automatic devices, etc.
2.0.12
DC power load
load of all kinds of DC motor, AC uninterruptible power supply, system telecontrol equipment, communication device power supply and emergency lighting, etc.
2.0.13
DC continuous load
load with power supplied reliably from DC power supply system both in its normal and emergency conditions
2.0.14
DC emergency load
load with power supplied reliably from the DC power supply system within the emergency power outage time of the AC power supply system
2.0.15
DC momentary load
large load current applied in a short time, which is classified into initial momentary load that occurs at the initial stage of emergency (1min) and random load that occurs at the end of or during the emergency (5s)
2.0.16
concentrated radiation DC power supply
power supply from the DC cabinet bus directly to the load or equipment terminal
2.0.17
layered radiation DC power supply
power supply firstly from the DC cabinet bus to the DC power distribution cabinet, and then from the DC power distribution cabinet bus to the equipment terminal
2.0.18
complete set of DC power supply
several DC power supply cabinets composed of storage battery, charging device, DC incoming circuit breaker and feeder circuit breaker installed in the cabinet, which may be arranged in relay room or power distribution room with other electrical equipment
2.0.19
AC and DC integrated power supply system
power supply system composed of AC power supply, DC power supply, AC uninterruptible power supply (UPS), inverter power supply (INV) and DC/DC converter and monitored and controlled uniformly, that is, the combination of DC power supply and any one or more of the AC UPS, INV and DC/DC converter that share DC storage battery
3 System design
3.1 DC power supply
3.1.1 Power plants, substations, series compensation stations and converter stations shall be provided with DC power supplies for control DC loads and DC power loads etc.
3.1.2 Storage battery shall be applied for 220 V and 110 V DC power supplies. The DC power supply at 48 V and below may apply the DC/DC converter for power which supplies power to the 220 V or the 110 V storage battery.
3.1.3 Under normal operation mode, the DC network of each group of the storage battery shall operate independently and shall not have any direct electrical connection with other storage batteries.
3.1.4 When the step-up station of the power plant is equipped with a computer monitoring and supervision system of power network, the independent DC power supply system of the step-up station of the power plant shall be set up.
3.1.5 When the single unit capacity is 300 MW or above and the auxiliary workshop of the power plant needs DC power supply, the independent DC power supply system shall be set up. When the power supply distance is far away, the auxiliary workshops of other power plants should be equipped with independent DC power supply system.
3.1.6 When the power supply distance is far away, the independent DC power supply system should be set in the series compensation or controllable high impedance equipment area of the substation.
3.1.7 The storage battery shall normally operate in floating charging mode.
3.1.8 Lead-acid storage battery shall not be equipped with the terminal battery; when the terminal battery is set in the nickel-cadmium alkaline storage battery, the number of terminal battery should be reduced.
3.2 System voltage
3.2.1 The DC power supply system voltage of power plants, substations, series compensation stations and current converter stations shall be determined according to the type, rated capacity, power supply distance and installation location etc. of the power consumptions equipment. The nominal voltage of DC power supply system shall meet the following requirements:
1 The voltage of DC power supply system for load control should apply 110 V or 220 V;
2 The voltage of DC power supply system special for the power load should apply 220 V;
3 The voltage of DC power supply system with combined power supply of control load and power load may apply 220 V or 110 V;
4 The DC control voltage of the whole plant (station) shall apply the same voltage, and the expansion and reconstruction project should be consistent with the DC voltage of the existing plant (station).
3.2.2 Under normal operation conditions, the DC bus voltage shall be 105% of the nominal voltage of the DC power supply system.
3.2.3 Under the condition of equalizing charge operation, the DC bus voltage shall meet the following requirements:
1 The DC power supply system special for load control shall not be higher than 110% of the nominal voltage of the DC power supply system;
2 The DC power supply system special for power load shall not be higher than 112.5% of the nominal voltage of the DC power supply system;
3 The DC power supply system with combined power supply for DC control load and DC power load shall not be higher than 110% of the nominal voltage of the DC power supply system.
3.2.4 At the last stage of accident discharge, the terminal voltage at the outlet of the storage battery shall not be lower than 87.5% of the nominal voltage of the DC power supply system.
1 General provisions
2 Terms
3 System design
3.1 DC power supply
3.2 System voltage
3.3 Storage battery
3.4 Charging device
3.5 Wiring mode
3.6 Network design
4 DC load
4.1 DC load classification
4.2 DC load statistics
5 Protection and supervision
5.1 Protection
5.2 Requirements of measure, signal and supervision
6 Equipment selection
6.1 Storage battery
6.2 Charging device
6.3 Cable
6.4 Discharge device for battery test
6.5 DC circuit breaker
6.6 Fuse
6.7 Disconnecting switch
6.8 Dropping equipment
6.9 DC Cabinet
6.10 Complete sets for DC power supply
6.11 DC/DC converter
6.12 DC motor starter
7 Equipment layout
7.1 Layout of DC equipment
7.2 Layout of valve-regulated lead-acid storage battery
7.3 Layout of vented lead-acid storage battery in fixed location and nickel-cadmium alkaline storage battery
8 Relevant requirements for dedicated battery room
8.1 Basic requirements for dedicated battery room
8.2 Special requirements for dedicated battery room of valve-regulated lead-acid (VRLA) storage battery
8.3 Special requirements for dedicated battery room of the vented lead-acid storage battery in fixed location and nickel-cadmium alkaline storage battery
Annex A Selection of DC circuit breaker
Annex B Information list of DC power system
Annex C Selection of battery
Annex D Selection of charger and rectifier module
Annex E Selection of cable cross section
Annex F Selection of storage battery circuit equipment and the main bus of DC cabinet
Annex G Calculation of short-circuit current for storage battery and the reference value table
Explanation of wording in this standard
List of quoted standards
