Intelligent distribution network – analysis of super capacitor technology

Intelligent distribution network – analysis of super capacitor technology

With the increase of power utilization links and the improvement of power utilization guarantee requirements, the grid operation level needs to be improved. With the further implementation and development of smart grid, the requirements for real-time response to faults are improved, and the timeliness of troubleshooting also needs to be guaranteed by the grid operators at any time. Therefore, the actual support time of the standby power supply after power failure does not need to be too long. In combination with the short-term fast charging response characteristics after power calls, The precondition of using super capacitor as power supply has been fully established.

At the same time, due to the large number of control equipment, the traditional battery power supply scheme can not be completely maintenance free (including the battery monitoring is also difficult to achieve), and at the same time, the reliability is not enough. It is difficult for grid operators to take into account a large number of equipment, so it is crucial to ensure the stability and reliability of equipment.

It is necessary to adopt completely maintenance free control power supply to ensure the stable operation of power grid!

What is a super capacitor?

Supercapacitor (Farad capacitor, gold capacitor) is a capacitor based on the principle that an inductive double charge layer is formed between the electronic conductor activated carbon and the ionic conductor organic or inorganic electrolyte. The charge distance of supercapacitors is much smaller than that of traditional capacitor dielectric materials, and the surface area of activated carbon electrode increases by an order of magnitude, which makes supercapacitors have super large electrostatic capacity compared with traditional capacitors, which is where their “super” lies.

Pseudo capacitive supercapacitor? A kind of chemical energy storage device that uses electrochemical energy storage and external characteristic curve like capacitor.

Application overview

1. Normal power supply: when the line is powered, the power module provides working power for DTU/FTU/LTU/TTU, and the super capacitor provides the electric opening/closing mechanism of the switchgear for operation.

2. Standby power supply: When the line loses power, the supercapacitor, as the energy terminal, provides the backup power supply for DTU/FTU/LTU/TTU through the power module, and drives the switch for opening and closing operation.

3. Scope of application: HCCCap super capacitor power supply system is applicable to power failure protection of ring network cabinets, switching stations, substations, column units and other places in the distribution network field, and is provided for the use of switch cabinets, intelligent units, communication and other systems and equipment.

Characteristics of super capacitor DC power supply

1. Super capacitors and power modules developed for intelligent terminals and various high-voltage switches;

2. Completely maintenance free, super capacitor and power module are maintenance free;

3. Reliable performance, built-in protection circuit, convenient combination of power modules;

4. Good temperature characteristics, especially excellent low-temperature characteristics, which can still work normally at – 40 ℃~+70 ℃;

5. Strong output current capacity to ensure the reliability of opening and closing;

6. Convenient customization, modular design, and can be adjusted according to customer needs;

7. Ultra long service life, up to 10 years;

8. Green energy, no pollution, no harmful metal components;

9. It has been widely used in the national network for more than 10 years.

Comparison of characteristics between super capacitor and battery

A Service life of the battery

The service life of 1-way battery is 2-3 years

2. The number of control links at the end of the distribution network is huge, and it is difficult to fully implement the maintenance link

3. It is difficult to ensure the absolute consistency of each single section in the service life, leading to the early failure of a single section, which will lead to the continuous deterioration of other series, and the performance degradation of the whole group will be accelerated

4. It is sensitive to high and low temperature, so the battery may begin to decay at an early stage

A Service life of super capacitor

1 Physical energy storage enables super capacitor monomer to have an ultra long service life

2 Avoid the accelerated failure problem caused by the difference of single branch, and ensure the life of the whole group

B

Battery maintainability

1 The battery often needs regular activation and maintenance

2 Maintenance free battery is not really “maintenance free”

3 Performance degradation caused by long-term full floating charge

4 Operation safety under regular maintenance

5. High operation and maintenance costs caused by large number of terminals

B Maintenance of super capacitor

1 Super capacitor is a completely maintenance free device, which does not require regular charging and discharging maintenance

2. It can be in working voltage state or voltage vacancy/semi vacancy state for a long time, and the working range of super capacitor can be between 0V and rated voltage

3 There is no over discharge problem, which has no excessive impact on the performance

C Reliability of battery

1 It is difficult to judge the state of the battery

2 The battery is in floating charge state at ordinary times. Even if the internal electrode plate is deteriorated, its terminal voltage may still be in a similar state to the new battery

3 It is difficult to conduct early warning and replacement, but once a large current discharge or deeper discharge is required, the terminal voltage will drop greatly, which cannot release a lot of electric energy and provide enough energy for DC link

4 The low temperature further aggravates the current output capability

5 In particular, important functions such as opening and closing cannot operate reliably and stably

Reliability of C super capacitor

1 The voltage of the super capacitor directly reflects its internal power storage, which is convenient for monitoring. Its state can be reflected by detecting the voltage or impedance, thus making the use of DC link and opening/closing more reliable and stable

2 Long service life and maintenance free characteristics determine its high reliability

D Temperature characteristics of the battery

1 The characteristics of the battery will decline rapidly at low temperatures. It is difficult to charge and discharge ordinary lead-acid batteries below 0 ℃, and the performance will decline sharply below – 20 ℃

2. The thermal insulation of storage battery will greatly increase the operation cost, especially in the control link at the end of the distribution network. The number is large, the environment is relatively harsh, and there are great hidden dangers in winter operation

3. The safety of lithium ion battery charging at low temperature is hidden

Temperature characteristics of D supercapacitor

1 The high and low temperature characteristics of the super capacitor are very good, especially the low temperature characteristics. It can still work normally at – 40 ℃, and can work normally without other insulation measures. Compared with the battery, it really saves energy and reduces carbon

2 HCCCap super capacitor still has more than 90% energy at – 40 ℃, ensuring stable and reliable operation of the power grid in winter

E Environmental protection characteristics of battery

1 The commonly used batteries have relatively large pollution, and a large number of use also brings about a great increase in the vulnerability of collection and treatment. It is inevitable to use as little as possible

2 In addition, acid leakage is almost an insurmountable problem. Under the conditions of long-term use, sealed cabinets and a large number of power grid end applications, acid mist and leakage will cause damage to the cabinet seal and electronic components (after the cabinet is damaged, the external environment will also cause accelerated damage to electronic components), reducing equipment reliability and increasing equipment replacement costs, In addition to maintaining the battery itself, the cost of manual maintenance of the equipment is also greatly increased

Environmental protection characteristics of E super capacitor

As a super capacitor of completely green energy, the electrode is made of activated carbon which is organic compatible with human body as adsorbent. It is pollution-free and does not contain any harmful metal components. It is the main force of the next generation of energy

2. Due to its characteristics, the device is required to be completely sealed, so a completely sealed structure is adopted in the design

3 The electrolyte is neutral electrolyte, even if the leakage occurs after mechanical damage, it will not greatly affect the equipment in the cabinet

F Charging and discharging characteristics of storage battery

1 Overdischarge of the battery will lead to invalid damage of the battery, and at the same time, when the battery is low

2. It is difficult to replenish enough energy to reach its normal working state when charging the empty battery for a short time, and the timeliness of system input is not guaranteed

Charge discharge characteristics of F supercapacitor

1 Even if the super capacitor loses power, it can still be charged and discharged normally once it is supplemented with energy, without affecting its characteristics

2 Super capacitor can replenish power quickly and efficiently with less energy, and can be put into operation immediately in a short time

Basic principles of super capacitor scheme design

Super capacitor direct supply, upper and lower voltage limits;

Make clear the load characteristics:

Average load and maximum load are converted through DC/DC;

Capacitance redundancy design;

Strong capacitance tolerance, positive deviation;

Capacitance balance reliability design, simple, solid and reliable.

Example of actual scheme calculation (for reference only)

1. Feeder terminal three remote FTU, average power consumption of core unit is usually<10W, wireless communication module is used for communication, keeping average power<3W online, circuit breaker meets opening requirements, 220V AC power supply is used at ordinary times, DC power supply is required to be 24V, and standby time is 15min

2. Capacitor module: 48F/27V

3. Power module, input AC 220V, dual output DC 24V, one directly supplying load, and the other charging capacitor bank, supports the instant opening and closing function of incoming calls

4. For power failure standby, the load is directly output by the capacitor, and the energy range is 27V~16V, which can support more than 15min

Note: For reference only, customized development can be made according to customer application requirements!

Model of ultracapacitor module of Holytech  smart grid

For more specifications and models, please contact Us directly

Voltage capacity range

27V series 2.5F~54F

29.7V series 20F~320F

30V series 10F~636F

54V series 3F~47F

48V series 165F~200F

60V series 2.5F~200F

Power related applications:

1. DTU ／ FTU/TTU/LTU power supply and power failure protection power supply

2. Operation power supply and power failure protection power supply of ring main unit/switching station/substation

3. Column switch operation power supply and power failure protection power supply

4. Power supply and power failure of communication module optical transceiver/carrier/wireless module

5. GPRS/GSM transmitting power supply of fault indicator

6. Load monitoring electric energy meter/electric energy meter concentrator/three-phase electric energy meter power failure communication power supply

7. Microgrid/distributed grid energy storage

8. Power quality adjustment/DVR power compensation power supply