1、 Product Overview:

The YH series DC screen provides power for controlling loads, power loads, 

and DC emergency lighting loads, and is the foundation of contemporary

 power system control and protection. The DC screen consists of an 

AC distribution unit, a charging module unit, a step-down silicon chain unit,

 a DC feeding unit, a distribution monitoring unit, a monitoring module unit, 

and an insulation monitoring unit. It is mainly used in small and

 medium-sized power plants, hydropower stations, various substations, 

and other users who use DC equipment (such as petrochemicals,

 mines, railways, etc.) in the power system. 

It is suitable for switch opening and closing, 

as well as instruments, meters, relay protection, 

and fault lighting in secondary circuits. DC screen is a new type of digital control, protection, 

management, and measurement DC system. 

The monitoring host is highly integrated and adopts a single board structure (All in one),

 which includes functions such as insulation monitoring, battery inspection, 

grounding line selection, battery activation, silicon chain voltage stabilization, 

and microcomputer central signal. The host is equipped with a large LCD touch screen, 

and various operating states and parameters are displayed in Chinese characters. 

The overall design is convenient and simple, with a user-friendly interface 

that conforms to user habits. The DC screen system provides powerful functions

 for remote detection and control, and has remote control, remote adjustment, 

telemetry, remote signaling functions, and remote communication interfaces.

 Through a remote communication interface, the operating parameters of the 

DC power system can be obtained remotely, and the operating status and settings can

 also be set and modified through this interface to meet the requirements o

f power automation and unmanned substations in the power system; Equipped

 with standard RS232/485 serial interface and Ethernet interface, it can be easily 

integrated into the power station automation system.

2、 Characteristics of YH series DC screen system:

① High reliability:

Adopting modular design with switch mode power supply and N+1 hot backup.

The charging module can be equipped with hot swapping, greatly reducing the 

average maintenance time.

The power bus and control bus can be directly powered separately

 by the charging module and can be backed up through a voltage reduction device.

Hardware low tolerance autonomous current sharing technology, 

with an output current imbalance between modules of less than 5%.

Reliable lightning protection and electrical insulation measures, 

insulation monitoring devices can monitor the insulation status of the system in real time, ensuring system and personal safety.

The system design adopts international standards such as IEC and UL, 

ensuring sufficient reliability and safety.

② High intelligence:

The monitoring module adopts a large screen LCD Chinese character 

display and sound and light alarms.

Parameter settings for various parts of the system can be made

 through the monitoring module. The module has the function of 

smoothly adjusting the output voltage and current, and has the 

function of compensating for battery charging temperature.

It has multiple extended communication ports and can be connected to

 various external intelligent devices (such as battery testers, insulation monitoring devices, etc.).

The combination of modern power electronics and computer 

network technology provides support for "telemetry, remote control, 

remote signaling, and remote adjustment" of power systems, achieving unmanned operation.

Automatic management and protection of batteries, real-time automatic

 detection of battery terminal voltage, charging and discharging current, 

and intelligent control of battery float charging. It is equipped with sound

 and light alarms for battery overvoltage, undervoltage, and charging overcurrent.

The system adopts monitoring devices with built-in insulation monitoring, 

battery detection, grounding line selection, battery activation, silicon chain voltage regulation, 

central signal and other functional units, greatly facilitating user use; The system adopts 

a unique "one wire connection" wiring technology, which greatly facilitates the on-screen 

wiring of high-capacity DC systems and facilitates user maintenance.

The charging module adopts natural cooling method, which greatly improves 

the average time between failures and can be used in relatively harsh environments;

The charging module can be plugged and unplugged with power, significantly

 reducing the average maintenance time;

Adopting international soft switching technology, the main components

 are high-quality products;

Hardware low tolerance autonomous current sharing technology,

 with output current imbalance between modules better than ± 5%;

Reliable lightning protection and high electrical insulation protection measures,

 with insulation monitoring devices monitoring the insulation status of the system 

in real time to ensure system and personal safety;

The monitoring module adopts a large screen LCD touch screen display and human voice alarm;

The monitoring program adopts an object-oriented design concept and modular programming,

 which is conducive to program maintenance and upgrading;

The monitoring module can be used to set the parameters of various parts of the system, 

with detailed online help functions;

Equipped with advanced functions such as smooth adjustment of output voltage and current, 

and automatic temperature compensation for batteries;

Combining modern power electronics technology with computer technology

 to achieve "telemetry, remote control, remote signaling, remote adjustment" of powersystems and unmanned operation;

● Automatic management and protection of batteries, real-time monitoring

 of battery terminal voltage, charging and discharging current, and control

 of battery equalization and float charging. Equipped with sound and light alarms

 for battery overvoltage, undervoltage, and charging overcurrent.

The device can provide program support through public telephone lines to 

achieve remote maintenance diagnosis - DC screen monitoring module.

3、 Main technical parameters

3.2.1 AC power supply device

(1) AC input voltage: three-phase 380V ± 20%

(2) Rated frequency: 50Hz ± 1%

(3) System grounding method: TN-S

3.2.2 DC power supply device

(1) AC input voltage: three-phase 380V ± 20%

(2) Rated frequency: 50Hz ± 1%

(3) System grounding method: TN-S

(4) Rated DC output voltage: DC220V

(5) Voltage ripple coefficient ≤ 0.5%

(6) Voltage stabilization accuracy ≤± 0.5%

(7) Steady current accuracy ≤± 1%

(8) Noise ≤ 55dB (1 meter away from the device)

(9) Comprehensive efficiency ≥ 90%

3.2.3 Design lifespan

Design lifespan: 30 years.

3.3 Technical performance and requirements of AC power supply device

3.3.1 Operation mode

The AC power supply device adopts a single busbar connection, and

 two power supplies are introduced from two sections of the AC400V busbar

 of the distribution transformer in this station as the incoming power supply

 of the AC power supply device. A dual power automatic switching device is installed.

3.3.2 AC incoming circuit breaker

The two incoming circuit breakers should be selected from reliable brands, 

equipped with electric operating mechanisms, shunt and voltage loss release devices, 

as well as phase loss protection and voltage detection relays. 

The overcurrent protection of the incoming circuit breaker should

 have the function of interlocking automatic switching device. 

The incoming line and bus tie circuit breaker adopt 4 levels; 

Rated capacity of circuit breaker: 100A; 

The short-circuit current breaking capacity of the circuit breaker shall not be less than 40kA.

3.3.3 AC feedback loop

The power distribution adopts busbar mode, and each output is equipped 

with high breaking circuit breakers with alarm auxiliary contacts. 

Each output is configured with signal indicators and other components,

 and the signal lights are energy-saving. 

The short-circuit current breaking capacity of the feedback circuit

 breaker shall not be less than 10kA, and reliable brand products shall

 be selected for the circuit breaker.

3.3.4 Automatic device

Each communication panel is equipped with a dual power automatic switching device. 

When one power supply fails, it automatically switches to the other power supply.

 The dual power automatic switching device can be manually or automatically switched on and off. The dual power automatic switching device must have a 3C certification report. The rated current shall not be lower than that of the incoming circuit breaker; The number of poles is 4; The electrical lifespan shall not be less than 6000 cycles, and the mechanical lifespan shall not be less than 10000 cycles.

3.3.5 Signal

Signals include two types: fault signals and working status indication signals.

3.3.5.1 Work status indication

Connect all power sources

Two power supply input

Mother Union Investment

Position signals of each feeder switch

3.3.5.2 Fault Signal

One power supply loses voltage

Overcurrent tripping of one power supply

Voltage loss of two-way power supply

Overcurrent tripping of two-way power supply

Fault in the mother coupling automatic switching device

3.3.6 Measurement Meter

There should be a voltmeter for one incoming power supply, 

a voltmeter for two incoming power supplies, and a three-phase ammeter on the panel.

3.4 Technical performance and requirements of DC power supply device

3.4.1 System composition

The DC power supply device consists of a charging device, a set of batteries, 

a feeder switch, an automatic (manual) voltage regulating

 device for the DC bus (the voltage regulating device is configured 

with two sets of main and backup), a microcomputer insulation monitoring device,

 and an intelligent monitoring unit. 

The charging device adopts high-frequency charging 

modules and hot redundancy (N+1) parallel configuration. 

When one charging module fails, 

it automatically switches to the backup module and displays a fault alarm on the touch screen, 

giving the reason for the alarm. 

The capacity of the charging device should meet the requirements of the system's regular

 load and battery charging current

The AC side of the charging device is connected to a three-phase 

AC380V power supply through an AC power supply device.

 During normal power supply, the charging device charges or

 float charges the battery pack, while providing power to

 the regular DC load of the entire station, which is supplied by the battery to the

 impact load. After the communication loses power, 

the battery supplies power to all loads inside the station (including regular loads and impact loads).

The DC bus adopts a single bus segmented connection method.

3.4.2 Charging device

The high-frequency switching power supply modular charging device is adopted,

 and its functional requirements are as follows:

The device should have charging (constant current, limited current and constant voltage), 

float charging, balanced charging, automatic switching 

of operation mode, autonomous current sharing function, 

and have soft start characteristics. The soft start time can be set according to user requirements.

The frequency of the switch power module is 20~300kHz.

The charging characteristics of the charging device should

 meet the requirements of the battery's characteristics.

The main technical parameters of the charging device should meet the requirements in Table 2.

3.4.2.1 Voltage and current limiting characteristics

3.4.2.1.1 Voltage limiting characteristics

1) Voltage limiting setting range: can be selected within the range

 of 105% to 145% of the rated voltage;

2) When the floating charging device operates in steady current charging mode, 

the device should be able to automatically limit the voltage and switch to 

constant voltage charging operation when the output DC voltage reaches the set voltage limit. 

The voltage stabilization accuracy of the voltage limiting characteristic should meet

 1.5 times the requirements in Table 2

3.4.2.1.2 Current limiting characteristics

2) Current limiting setting range: 50% to 110% of the rated output current;

2) When the charging float charging device operates in a stable voltage

 charging mode, it should have charging current limiting and output total current limiting 

functions. If the load current exceeds the set value of the current limiting, 

the device should be able to automatically limit the output current, 

and the output current should immediately drop below the set value.

3.4.2.2 Stable voltage regulation range

1) Voltage regulation range in float charging state: 95% to 115% of rated voltage;

2) Voltage regulation range under balanced charging state: 105% to 120% of rated voltage.

3.4.2.3 Efficiency

The efficiency of the high-frequency switching power supply type charging device should be ≥ 94%.

3.4.2.4 Requirements for current equalization

When multiple high-frequency switching power supply modules of the same specification and model are operated in parallel, their current imbalance should meet the requirements of Table 3.

3.4.2.5 Power factor

When the output power of a single module is ≥ 1500W, the power factor should be>0.95;

When the power output of a single module

3.4.2.6 Other requirements for charging module

(1) It should be able to operate independently without the monitoring unit.

(2) Compensate for battery charging voltage based on temperature changes.

(3) It has protective measures such as overcurrent, overvoltage, 

short circuit, phase loss, high/low AC voltage shutdown, etc.

(4) Can be plugged and unplugged with power.

(5) There are good ventilation, heat dissipation, dust and moisture prevention measures.

(6) The function of preventing overcharging of the battery.

3.4.3 Functional requirements for DC power supply devices

Load capacity and continuous power supply

(1) The equipment operates under normal float charging conditions.

 When providing an impulse load, it is required that the voltage on its DC bus should 

not be lower than 90% of the DC nominal voltage during the impulse discharge time.

(2) During normal operation of the equipment, if the AC power supply

 suddenly interrupts, the DC bus should continue to supply power, 

and the fluctuation of the DC bus should not be lower than 90% of the nominal DC voltage.

3.5 Function of Voltage Adjustment Device

Adopting a primary and backup automatic voltage regulation device,

 when the main voltage regulation device fails, the backup voltage regulation device will

 automatically activate and send alarm signals to the local and remote areas. 

The voltage regulation value of each level is less than ± 3% of the rated voltage,

 and the voltage regulating device should have manual and automatic voltage 

regulation functions. The DC bus voltage during charging should

 not exceed 10% of the rated voltage.

3.6 Insulation Supervision Requirements

Adopting a microcomputer based insulation monitoring device, 

the insulation monitoring level should not be less than 50k Ω. 

The insulation monitoring device should be able to measure

 and judge the insulation resistance of the busbar to

 ground and the insulation condition of each feeder branch. 

When a grounding fault occurs in the DC

 system of the equipment (positive grounding, negative grounding, or both positive 

and negative grounding), and the insulation level drops beyond the normal range, 

a light alarm signal should be issued locally and uploaded to the comprehensive automation system.

 The device should be able to correctly indicate the faulty feeder branch and grounding polarity,

 directly display the bus to ground resistance, and manually 

set the threshold for grounding resistance.

3.7 Voltage Monitoring Requirements

The voltage insulation monitoring device should be able to monitor the 

voltage of the control bus and issue alarm signals locally and remotely when the DC 

bus voltage is higher or lower than the specified value.

 The voltage insulation monitoring device should be equipped with instruments 

or LCD screens with direct reading function. The return coefficient of overvoltage

 relays should not be less than 0.95, and the return coefficient of undervoltage 

relays should not be greater than 1.05.

3.8 Fault alarm requirements

When the AC power supply loses voltage (including phase failure), 

the charging float charging device malfunctions, or the battery pack fuse (circuit breaker) trips, 

the equipment should be able to reliably issue an alarm signal.

Functional requirements for monitoring unit

3.9 Control Function

The monitoring unit adopts a microcomputer type product and should have 

control programs for charging, long-term operation,

 and AC interruption. According to the charging characteristic curve and characteristics of the battery,

 the charging module should be controlled to automatically complete

 the charging and charging mode conversion of the battery. Effectively control the

 charging voltage and current of the battery to extend its lifespan.