Detail interpretation of the new energy power supply system
Time of issue:2021-12-15
5. New energy power supply system
5.1 Composition of solar power supply system
5.1.1 Solar cell phalanx
Energy storage device: generally valve-regulated sealed lead-acid battery.
Power distribution device: the solar controller, which is used to control the charging of the battery by the solar battery and the discharge of the battery to the communication equipment. The system controller also has a temperature sensor, a smoke sensor, a battery circuit fuse auxiliary contact, and a solar battery array auxiliary Contacts and access control contacts, etc.
Voltage conversion device (individual): Only used when supplying communication equipment with different voltages.
5.1.2 Solar Power Supply System-Operation Mode
When there is light, the solar battery controller controls the charging of the battery by the solar battery, and the fully charged battery discharges and supplies power to the communication equipment through the solar battery controller. Generally, the designed battery capacity is large, and the discharge voltage of the battery is not low enough. The solar cell will charge the battery again the next day, so that the charging and discharging cycle will maintain uninterrupted power supply. If there is no sun for several consecutive days, the battery cannot be charged in time, and when the discharge voltage is lower than the predetermined value, the solar battery controller The load will be disconnected in time to protect the battery from over-discharge.
5.1.3 Solar Power Supply System-Installation Method
The installation location of the solar cell phalanx is related to the capacity. The installation location is different, and the issues to be considered in the installation design are also different.
The solar cell arrays of the small independent photovoltaic power generation system can be installed on outdoor poles or towers, and the solar cell arrays can be fixed on the iron support of the poles and towers.
Regardless of whether the medium-sized photovoltaic power generation system is independent or hybrid, its solar cell arrays are mostly placed on the roof platform of the building or on the iron beam supported by the concrete column, and a few are installed on the ground.
The solar cell array of the large-scale photovoltaic power generation system occupies a large area and should be installed on the ground.
5.1.4 Solar Power Supply System-Capacity Calculation
|The relationship between total annual radiation and light intensity correction coefficient(η), noon light intensity correction coefficient(ηb)|
|Total annual radiation||η||ηb|
P: The total capacity of the solar cell array (W).
Up: The operating point voltage (V) obtained by a solar cell module under standard test conditions.
I: Load current (A).
ηb: Ampere-hour efficiency of battery charging, 0.84 for lead-acid battery.
T: The local sunshine hours per year (h).
Uo: The float voltage (V) of each battery.
Nb: The number of batteries in each group.
U1: The voltage drop (V) caused by the components and wires connected in series with the solar battery to the battery power supply circuit in the floating charging mode.
Fc: The comprehensive correction coefficient that affects the power generation of solar cells, generally 1.2-1.5.
η: The light intensity correction coefficient obtained by converting the local average daily sunshine into the standard test condition light hours, generally 0.6-2.3.
α: The temperature coefficient of voltage of a single cell in a solar battery group, its value is -0.002--0.0022V/°C.
t1: Working temperature of solar cell module (°C).
t2: Standard test temperature of solar cells (°C).
Nm: The number of single solar cells connected in series in a solar cell module.
8760: The average number of hours per year (h ).
5.1.5 Solar base station
5.2 Wind power system
5.2.1 Composition of wind power generation system
Dummy load of wind turbine.
Power distribution device.
Energy storage device: generally a valve-regulated lead-acid battery.
Voltage conversion device: It is only used when the communication equipment of different voltage is supplied at the same time.
5.2.2 Wind Turbine-Principle
Wind turbines are mainly composed of wind energy collection devices, transmission mechanisms and generators. The wind energy collection devices and transmission mechanisms are different due to different power generation capacity. The capacity of wind turbines for communication in my country is small, and more conventional paddle-type wind wheels are used. As a wind energy collection device, the generator is fixed on the same rotating shaft, so that the transmission mechanism is omitted. The rotation of the paddle-type wind wheel has three types: resistance type, lift type, and resistance-lift combined type.
Wind turbine power generation is affected by climatic conditions. Only when the wind is greater than the starting wind speed of the wind turbine can it rotate and generate electricity. In order to make full use of the wind, when the wind direction changes, the wind wheel must also be adjusted to the wind. Small or micro wind turbines can be used. The direction of the tail wing, medium and large wind turbines are mostly adjusted by auxiliary wind wheels.
When the wind turbine is running at a wind speed greater than the starting wind speed, within a certain range of wind speed, the greater the wind speed, the more power generation. In order to prevent the wind wheel from experiencing large fluctuations in the rotation speed when the wind speed changes, and to prevent it from being caused by high winds. Overspeed causes damage, and wind wheels generally have speed control devices. There are two types of speed control systems:
One is that the blade pitch is fixed. When the wind speed increases, the auxiliary side wings or the tilted hinged tail and other aerodynamic mechanisms make the wind wheel rotate around the vertical axis, deviate from the wind direction, reduce the windward surface, and achieve the purpose of speed regulation.
One is that the blade pitch can be changed. When the wind speed changes, the aerodynamic pressure or centrifugal force caused by the rotation of the wind wheel is used to change the pitch to achieve speed regulation. When the wind speed exceeds the limit value, the wind turbine can achieve "tail folding" protection, so The wheel plane is parallel to the wind direction, and the power generation is stopped.
Wind turbines for communication usually use brushless three-phase permanent magnet AC generators (permanent magnet DC generators are also used). The windings are fixed on an independent stator made of non-ferromagnetic synthetic materials. Magnets will not lock the running wind turbine, thus eliminating iron loss, and enabling the wind turbine to work at the highest efficiency under common low wind speeds.
5.2.3 Wind turbines-classification
Communication bureaus (stations) generally use small horizontal-axis three-phase AC wind turbines and their supporting fan dummy loads, as well as rectification, control, and power distribution equipment.
According to the different power generation capacity, it is divided into large-scale (above 50kW), medium-scale (10-50kW), small-scale (1-10kW), and micro-scale (below 1kW).
According to the form of the fan, it can be divided into three types: vertical shaft type, horizontal shaft type (common) and free type (smaller capacity).
According to the rated power of the generator, it can be divided into AC and DC. AC is divided into single-phase and three-phase. Three-phase AC wind turbines are more common.
5.2.4 Wind turbine-wind turbine controller
The fan controller includes two parts: the finisher and the controller.
The rectifier uses the principle of semiconductor rectification to convert the alternating current generated by the wind turbine into direct current when the communication equipment needs it.
The controller uses a single-chip microcomputer to receive the command signal from the main control machine to control the wind generator.
Control wind turbines to switch on or withdraw power to communication equipment. When the power supply is removed, the false load of the fan is thrown in advance to ensure that the fan avoids running in an open circuit state and causing runaway.
5.2.5 Wind Turbine-Fan Dummy Load
The dummy load of the wind turbine is a resistance box, which uses the principle of generating heat through the resistance and the method of heat dissipation to convert the excess electric energy produced by the wind turbine into heat and dissipate it into the air, so as to ensure that the wind turbine is always running under load. state.
Wind turbine dummy load is a special equipment produced according to the requirements of wind turbines. Its voltage, power and service life are matched with those of wind turbines. Due to the constant heat dissipation during work, safety and ventilation are considered.
5.2.6 Wind Turbine-Capacity Calculation
The wind turbine cannot rotate when the wind speed is lower than the starting wind speed of the wind turbine. It starts to rotate and generate electricity at the starting wind speed. When operating at a speed greater than the starting wind speed, within a certain wind speed range, the power generation and the wind speed follow a certain curve law (approximately into Proportional) transformation. When the wind speed exceeds the limit value, the wind turbine stops rotating and no longer generates electricity.
Within the power generation wind speed range, the expression of the wind wheel power is:
Cp: The power coefficient of the wind wheel (wind energy utilization coefficient), its ideal value is approximately equal to 0.593, and the value of modern wind turbines can reach 0.40.
A: The working area of the wind turbine (the swept area of the blade).
p: air mass density.
v: Air velocity.
Modern horizontal-axis wind turbines usually use high-speed lift-type wind wheels.
5.2.7 Selection of wind turbine
Selection of wind turbine: The capacity of the wind turbine must meet the communication load requirements under the annual average wind speed.
Selection of the wind turbine controller: The wind turbine controller is the supporting equipment of the wind turbine produced by the wind turbine manufacturer. Once the wind turbine is selected, the wind turbine controller is selected at the same time.
Selection of the dummy load of the wind turbine: The input voltage and power of the dummy load (resistance box) of the wind turbine must meet the requirements of the wind turbine.
5.2.8 Wind power base station
6. Generator power supply system
6.1 Function of generator set
The role of the generator set is to act as a long-term backup power source
The Principles for the selection of generator sets (YD/T 5040-2005):
Diesel generator sets should be selected for stationary power generation equipment;
For bureaus (stations) with a single unit capacity exceeding 1600kW, gas turbine generator sets can be used;
Gas turbine generator sets should be selected for vehicle-mounted generator sets with a capacity of 800kW and above.
6.2 Gasoline generator set
6.2.1 Selection of gasoline generator set
The capacity should meet the needs of the whole station to ensure the power supply of the load.
According to the size of the load, when the load is less than 10KW, a gasoline generator should be used.
If the fuel supply is convenient, it will be used first under the same conditions.
6.2.2 Installation of gasoline generator set
Generally, there is no need for fixed installation, just put it on a level concrete floor.
Indoors are required to be well ventilated, and fire protection meets relevant regulations.
6.3 Diesel generator set
6.3.1 Diesel generator sets-classification
Diesel generator set is a power supply equipment that burns diesel internal combustion engine to drive generator to generate electricity.
According to the installation method: mobile, fixed
Wind according to heat dissipation method: air-cooled, water-cooled
According to operating conditions and degree of automation: manual operation, automatic start and stop, unattended
According to the movement of the piston in the cylinder: four-stroke, two-stroke
According to diesel engine operating speed: high speed (n ≥1000r/min), medium speed (300r/min<n<1000r/min), low speed (n≤300r/min)
According to the start mode: electric start, hand crank, compressed air start
According to the intake of diesel engine cylinders: general type, supercharged type
According to the voltage level of the generator: general, high voltage
6.3.2 Diesel generator set-composition
The performance of a diesel generator set is determined by the various systems that make up the diesel generator set:
The starting system includes manual starting, electric starting, and compressed air starting.
The fuel (fuel) supply system consists of fuel tank, fuel filter (coarse and fine), fuel pump, restrictor valve and injection
6.3.3 The oiler is composed of oil pipe connection.
The lubrication system consists of a lubricating oil pump (oil pump), a lubricating oil filter, an oil cooler, an oil collecting tank and an engine lubricating oil delivery pipeline.
The cooling system is air-cooled, open-loop water-cooled, and closed-loop water-cooled.
The intake and exhaust (smoke) system is composed of air filter (coarse and fine), cylinder and external exhaust pipe, flexible connection (corrugated pipe), muffler, etc.
Excitation system includes brushless excitation, manual excitation device, controllable and uncontrollable phase compound excitation device, thyristor excitation regulator, DC generator excitation, semiconductor excitation system (self-excitation, separate excitation), harmonic excitation, etc.
6.3.4 Determination of the capacity of fixed diesel generator sets
Floating charging power of various DC power supplies + charging power of battery packs;
Power of communication equipment with AC power supply;
Ensure the power of air conditioner;
Ensure lighting power;
Others must ensure the power of the equipment.
For AC uninterruptible power supply equipment (UPS), when verifying the power required by the generator set, it should be determined according to the magnitude of the input current harmonic content. When the input current harmonic content is 5%-15%, the required power generation The guaranteed power of the unit is calculated at 1.6-2 times the UPS capacity.
6.3.5 Diesel generator set selection
The capacity should meet the needs of the whole station to ensure the power supply of the load.
The unit should be able to output rated power and work normally under the following environmental conditions:
Ambient temperature: -5℃～＋40℃;
Relative air humidity: ≤90% (25℃).
When the diesel generator set works under non-standard atmospheric pressure, the power should be corrected. The simple calculation method is:
P: The output power (kW) of the diesel generator set under non-standard atmospheric pressure.
Ne: The rated power of the diesel engine under standard atmospheric pressure (hp, 1hp=0.7355kw).
C: Comprehensive correction coefficient of temperature, humidity and atmospheric pressure of diesel engine under non-standard atmospheric conditions.
Nf: Fan power consumption (hp).
K1: power conversion constant.
N: Generator efficiency.
6.3.6 Fuel consumption of diesel generator set
Under the rated working conditions of the unit, the fuel and engine oil should not exceed the following ranges:
|Unit rated power(kW)||P≤10||10＜P≤24||24＜P≤40||40＜P≤75||75＜P≤120||120＜P≤250||250＜P≤600||600＜P≤1250||1250＜P≤2000|
|Unit rated power(kW)||P≤10||10＜P≤40||40＜P≤1250||1250＜P|
|Oil consumption rate(g/kW•h)||4||3.5||3||2.8|
6.3.7 Installation of fixed diesel generator set
Air inlet and outlet: unblocked, with sufficient area.
The area of the air inlet is generally 1.8 times the area of the radiator of the unit;
The area of the air outlet is generally 1.5 times the area of the radiator of the unit.
Noise reduction treatment: meet the requirements of environmental protection.
Set up the inlet air silencing room and the exhaust air silencing room,
The depth of the muffler room is generally 1.5-2m,
Sound-absorbing materials are installed on the indoor walls,
The exhaust pipe is equipped with a silencer.
Installation foundation: load-bearing, stable, concrete pouring, and damping grooves.
Low smoke treatment: sedimentation method, water spray method, chemical spray method.
Computer room location: In order to avoid noise and vibration, it is generally separated from the communication room.
6.3.8 Noise reduction treatment of stationary diesel generator sets
■Main and standby mode
Two units working in the main-standby mode can be used as the main or standby unit by setting any unit, and the two units have mechanical and electrical interlocking. When the main unit fails to start, the standby unit is automatically controlled to start. After the mains incoming signal is delayed, the output switch of the unit will be switched off, and the running unit will automatically stop after 5 minutes of no-load operation.
For a generator set working in parallel mode, when the start signal is received, two sets are started at the same time. Only after the parallel connection is successful, the load will be supplied. When the load is less than 80% of the rated power of a single set, one set will be automatically released; When it reaches 85%, another unit is automatically started and integrated into the power supply. After the mains incoming signal is confirmed after a delay, the unit will automatically cut off the unit's output and stop automatically after 5 minutes of no-load operation.
The conditions for parallel operation of two diesel generator sets are: equal voltage, equal frequency and equal phase.
The conversion between mains and diesel generators should adopt mechanical and electrical interlocking and have mains priority power supply function, and ATS should be adopted.
6.3.9 Setting of oil engine room
The generator room should be arranged on the back of the building as far as possible, and should not be arranged at the main entrance, adjacent or above and below the main entrance of the building.
It is necessary to consider the handling of the generator. Submit the size and weight of the generator to the civil engineering department to plan the transportation channel and floor load. Secondly, consider the generator's air inlet, exhaust, and smoke exhaust ducts. For those installed on the first floor, if conditions permit, the two walls of the diesel generator room should be placed directly against the outside, with one side for air intake and the other for exhaust air.
Set up an automatic fire extinguishing system and an automatic fire alarm system. The generator room is equipped with a first-level ordinary temperature detector (operating temperature is 62 ℃) and a first-class ordinary photoelectric smoke detector, which are connected to the gas fire extinguishing control panel. The gas fire extinguishing control panel can independently complete the linkage control of fire detection and gas fire extinguishing device systems in the gas fire zone, and send the fire alarm, fault status, cylinder jet, and automatic manual status to the fire control room through the module for alarm display and related fire protection Linkage control.
6.3.10 Fuel tank settings
According to Article 220.127.116.11 of JGJ/T16-92 "Code for Electrical Design of Civil Buildings": Set daily fuel tanks according to diesel engine operation for 3-8h; and in accordance with Article 18.104.22.168 of GB50045-95 "Code for Fire Protection Design of High-Rise Civil Buildings" Regulation: The volume of the intermediate tank should not be greater than 1m³. In the design, regardless of the capacity of the diesel engine, the fuel tank is set for a generator corresponding to a fuel tank with a volume not greater than 1m³. The 1m³ fuel tank of a larger diesel generator set can only run for 3-4 hours, and cannot meet the mains power outage. Long-term requirements, so in practical applications, the problem of long-term fuel supply can be solved by setting up underground oil depots and mobile oil trucks.
Structure diagram of stationary gas turbine generator set
Common oil engine generator set