Discussion on the application of electric vehicle charging piles in the transformation of old urban communities

Ren Yunye Ankerui Electric Co.
, Ltd.
Shanghai Jiading 201801 Abstract: The 2020 Government Work Report points out: Strengthen the construction of new infrastructure, develop a new generation of information networks, expand 5G applications, build data centers, increase charging piles, power stations and other facilities, promote new energy vehicles, stimulate new consumer demand, and help industrial upgrading
.

As a supporting facility for the development and promotion of the new energy vehicle industry, charging piles will usher in high-speed development opportunities
.

The "Implementation of Urban Renewal Action" makes it clear that strengthening the transformation of old urban communities is a major people's livelihood project and development project
.

At present, under the impetus of multiple policies, various localities have formulated technical guidelines, and the transformation of old residential areas is divided into "basic category", "improvement category" and "promotion category"
.

The release of the "New Infrastructure" launched by the National Development and Reform Commission and the "Implementation Opinions on Further Improving the Service Guarantee Capability of Electric Vehicle Charging Infrastructure" (Development and Reform Energy Regulation [2022] No.
53) will increase the pace of construction of charging piles in old residential areas and actively meet the urgent needs
of residents in old residential areas for electric vehicle charging.

Keywords: Charging pile transformer safety 1 trend analysis According to GB/T 51313 - 2018 "Engineering Technical Standards for Decentralized Charging Facilities for Electric Vehicles" (hereinafter referred to as "Vehicle Charging Standards") Article 3.
0.
2, paragraph 1: "Newly built residential parking spaces should be 100% of the construction of charging facilities or reserved construction and installation conditions" does not apply to the transformation
of old residential areas.

Because the old residential areas are generally built before the end of 2000, unlike the "demolition and reconstruction" of shed reform, but on the basis of the existing "file upgrading", it can only be based on paragraph 3 of Article 3.
0.
2: "The existing parking spaces are equipped with decentralized charging facilities, and it is advisable to combine the charging needs of electric vehicles and the current situation of the distribution network to plan rationally and implement step by step.
"

Because the old residential area did not involve electric vehicle charging facilities in the previous electricity consumption plan, the transformer capacity designed at that time was also close to saturation due to the gradual increase of the load capacity of power development, resulting in the installation of charging piles in the later period becoming very difficult
.

This paper does not discuss the difficult problems such as the difficulty of selecting the installation location of charging facilities and the increase in capacity affecting the normal operation of the power grid in the community, but only discusses how to add as many charging pile applications as possible in the old residential areas without increasing the capacity to meet the strong needs
of residents.

The author investigated two typical old residential areas in the city in the 1990s, one is a hospital family home (referred to as District A), and the other is a multi-storey residential community (referred to as Area B
).

A community transformer in addition to the residential electricity also bears a part of the hospital's auxiliary room electricity, including gas boiler room, canteen, logistics office, boiler room load capacity of 60 kW only in winter; B district transformer bears residential electricity and frontage shop electricity, transformer load rate survey data as shown in
Table 1.

From Table 1, it can be seen that the A cell transformer still has some redundancy, and the B cell transformer capacity is close to saturation, and there is no possibility of expansion, but the valley-peak difference is relatively large
.

After the survey, residents have a demand for charging piles, and the property department is helpless due to insufficient power load, fewer parking spaces, how to charge, how to choose charging piles, charging safety and other issues
.

After the author's communication, the property department said that as long as it does not increase capacity, it is also willing to find a way to transform and increase the charging pile, after all, this is the trend of the times, and it is also the requirement of "upgrading" in the transformation of
old residential areas.

Table 1 Load rate of old cell transformer 2 Selection and application of charging piles in the transformation of old residential areas Electric vehicle charging piles are divided into two categories: AC and DC, as shown in
Table 2.

In view of the fact that the charging pile has the characteristics of "AC slow charging" and "DC fast charging", combined with the travel law of residents in old residential areas, it allows for a long continuous charging time, especially the residential users in areas with peak and valley electricity price adjustment are more sensitive to electricity prices, and it is suitable for choosing the "AC slow charging" method
.

AC charging pile can be used by connecting 220 V power supply, and the charging power of AC single-phase charging pile is 7 kW and the current is less than 32A; The charging power of the DC charging pile is generally above 30 kW, and the input current of the single gun is large, which is a huge test for the transformer capacity and power supply line, and the general old residential area or even one cannot be
installed.

From the perspective of installation, the installation cost of DC charging piles is relatively high, and the line laying is even higher
than the cost of equipment.

Therefore, the AC single-phase 7kW slow charging pile is suitable for the transformation
of old residential areas.

Electric vehicle charging has intermittent and irregularity, centralized charging can easily lead to the overlap of the conventional power peak of the power grid, which will affect the normal operation of the residential power grid, only by implementing the distribution of staggered peak charging, can we avoid the overlap between the charging load and the peak period of the
domestic electricity load.

In this way, in the case of no increase in the capacity of the existing residential transformer, by formulating an orderly charging power strategy for electric vehicles and reasonably controlling the output power, the charging needs
of the vehicle can be met.

Table 2 Electric vehicle charging pile classification 3 time-sharing orderly charging system solution Figure 1 System diagram For the application problems of charging piles in the transformation of old residential areas, the time-sharing and orderly charging management system of electric vehicle charging piles can meet the transformation needs
of old residential areas.

The system dynamically controls the number of charging piles on the line and charging output by monitoring the power limit of the distribution transformer, the real-time load and the control instructions of the higher-level system, so as to realize the coordinated scheduling of the "vehicle-pile-network" of the residential power grid, as shown in
Figure 1.

The distribution monitoring and management device realizes Ethernet communication between the communication unit and the network operation management platform, measures the capacity of the distribution transformer, real-time uploads the parameters of voltage, current, power, load redundancy and other parameters in the distribution network, and the operation management cloud platform controls the operation status of the charging pile such as access, exit, charging and auxiliary source output according to the power grid parameter information; The network operation management platform is connected to the main control unit of AC charging pile and the main control unit of DC charging pile through Ethernet communication, respectively; AC charging pile and DC charging pile are through the charging pile main control unit, protection and monitoring unit, card swipe unit, metering unit, cost settlement unit, human-computer interaction unit, output unit, auxiliary power switching unit to achieve AC charging pile and DC charging pile control guidance, safety protection and monitoring, human-computer interaction, metering and cost accounting, charging record and fault information storage; The network operation management platform communicates with the mobile APP client
.

Real-time monitoring of transformer load, when the load exceeds 50%, the system will limit the power of the charging pile that is newly charged, reduced to 50%, when the transformer load exceeds 80%, the system will not allow the new charging pile to start charging, until the load drops, greatly improving the ability of the distribution network to manage the charging pile, in the case of no residential distribution network upgrading, so that the installation of charging piles increases, while achieving the goal of grid peak shaving and valley filling
。
ASCP200-40B fireproof current limit protector is specially designed to protect the low-voltage distribution line in the short circuit, overload, overtemperature, leakage and over/undervoltage and other problems of research and development, can effectively overcome the traditional circuit breaker, air switch and monitoring equipment existing in the short circuit current, cut off short circuit current time is long, short circuit generated when the arc spark is large, and short service life and other drawbacks, when the short circuit fault occurs, can quickly limit the short circuit current at a microsecond speed to achieve arc extinguishing protection.
This can significantly reduce electrical fire accidents and ensure the safety
of personnel and property in the use of places.

4 Conclusion The addition of charging facilities in the transformation of old urban communities is an important measure to drive the consumption of electric vehicles, low-carbon life, and promote green development, and designers should design safe charging facilities according to the actual situation of the community, and deploy
them as far as possible without upgrading the distribution network of the community.

And through the intelligent Internet of things, time-sharing sharing, orderly charging and other new technologies to achieve electric vehicles to participate in power operation peak shaving and valley filling, improve the efficiency of the power grid, and promote charging piles to play an important role
in the construction of smart transportation and smart cities.

About author:Ren Yunye, male, currently working at Acquaray Electric Co.
, Ltd.