How to solve power quality problems under the late

2022-07-29
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How to solve the problem of power quality under the wave of new power reform

with the rapid progress of power reform, power selling companies have risen to the clouds. How to establish core competitiveness before the formation of the real power market has become the focus of power selling companies. In the mature power market, as a product, the competitiveness of power products is reflected in three aspects: price, quality and service. This exchange will share with you the power quality issues under the background of power reform

topic background

in 2015, the national energy administration and the national development and Reform Commission issued a series of documents related to power reform. The most fundamental of these documents is to orderly liberalize the power distribution business to social capital. When the policy was just released, most people in the industry did not know how to participate. No matter the power generation enterprises, the original power companies or small social capital companies, they all thought that they should occupy a place first, so they established many power distribution companies

according to my personal understanding, the so-called deregulation of electricity rationing business to social capital refers to enterprises of this type that can really do it to large capital or objects with certain resources. However, this does not mean that private capital does not have the opportunity to participate, because the deregulation of the entire electricity rationing market will bring a lot of additional services, which is an area that everyone can participate in

1. Typical mode of energy service company

for market participants after the power reform, I think it is more appropriate to call them energy service companies, because the services provided for industrial parks, commercial parks or residential parks in the future must be comprehensive energy services. The main businesses of integrated energy service providers are as follows:

load collection

providing power consumption optimization for users

research at home and abroad has confirmed that the distributed energy construction

power consumption service

power consumption service here is a brief list of four points:

quadruple collection of water, electricity and gas: the marginal cost of service is close to zero

hosting and maintenance: online request + offline service, Increase user stickiness

differentiated services: design specific energy service schemes for specific users

demand side response: gather power users to sign agreements and participate in demand side response

2. Competitiveness of energy service companies

in the energy service market or power market, power, as a product, undoubtedly includes these three elements: service, price and quality

in terms of services, power enterprises have done very well, especially for some large users or large complexes, or some important political users

before the power reform, before entering the power market, the prices were set uniformly by the national development and Reform Commission, and there was basically no room for bargaining. After the establishment of the power market, when the power purchase volume reaches a certain scale, you can negotiate with the power generation enterprises or users, or the user side can include value-added services in the electricity price

quality is a relatively broad concept, not only power supply quality, but also service quality and response to user demands. Here we will discuss the power quality

I. interpretation of power quality problems

1. Definition and characteristics of power quality

from an academic point of view, that is, in a narrow sense, power quality problems mainly include the following:

voltage rise/fall

harmonic

voltage fluctuation and flicker

three-phase imbalance

short-time interruption

frequency deviation

voltage rise/fall can be understood as the rise or fall of power supply voltage in a short time; The most intuitive understanding of voltage fluctuation and flicker is that the incandescent lamp will flash when the voltage fluctuates or flickers. Of course, power quality also includes voltage, current and other issues

from the perspective of energy service or power service, the definition of power quality is broader, which can be simply divided into the following four categories:

voltage quality: including voltage deviation, voltage frequency deviation, voltage imbalance, voltage transient, voltage fluctuation and flicker, voltage sag (rise) and interruption, voltage harmonic, voltage notch, undervoltage, overvoltage and other problems

current quality: current quality is closely related to voltage quality. Current quality includes current harmonics, interharmonics or subharmonics, current phase lead or lag, noise, etc

power supply quality: including technical meaning (voltage quality and power supply reliability are not optimistic about the export amount in the first half of this year) and non-technical meaning (the response speed of power supply departments to user complaints and complaints and the transparency of power prices, etc.). At present, power companies have done a good job in customer service, However, the existing power system or the operating mechanism of the existing power companies and the existing power consumption policies may bring certain limitations. Some businesses are not that the power companies do not want to do it, but that there is no policy basis on the one hand, and on the other hand, they do not know what to do in terms of investment

power quality: the real power quality is composed of power consumption and power supply. Power quality also includes technical and non-technical meanings. In terms of technical meaning, for users, whether the electric equipment will cause some power quality problems, such as whether it will inject harmonics into the electricity, whether it will exceed the reactive power limit, etc., at present, the power company has defined these two blocks, and also has relevant management measures. Whether it is the reactive power limit or the harmonic limit, it will be fined. The non-technical meaning of power quality is the users' understanding of power quality problems, such as some characteristics of equipment when power quality problems occur. These users should have a certain understanding, but not many users really know

2. Characteristics of power quality problems

power quality problems have their own characteristics:

power quality in the power system is always in dynamic change, which depends on: (1) the power flow of the power system itself is constantly changing; (2) Most user behaviors are random for power system

the power system is a whole, and its power quality is the result of the joint action of electricity, users and power plants. Electric energy is not easy to store, and its production, transmission, distribution, conversion and consumption are almost carried out at the same time

power quality disturbances are potentially harmful and widespread. The harmfulness is mainly aimed at the user side. Power quality problems will bring economic, physical and even political harm to users. Power is a whole. Power quality problems occurring at one point will affect a large range, which is the wide spread of power quality

in some cases, the user is the main part to ensure the power quality, especially in modern industrial conditions, because a large number of DC loads are used in modern industry. These loads are nonlinear and will inject harmonics and reactive power into the electricity, which leads to some power quality problems

it is very difficult to comprehensively evaluate the power quality indicators of the power system, which is mainly reflected in the following aspects: power quality events, especially temporary voltage rise/fall and short-term voltage interruption, are highly random and inevitable. It is actually very difficult to evaluate the power quality of a specific area. At present, it is mainly to use big data technology to mine historical data and obtain some reference quantities for evaluation, However, due to regional differences, even if big data is used, there will be some difficulties

control and management of power quality in power system is a systematic project, which is closely related to factors such as the cause and propagation characteristics of power quality. It is immature to consider only one aspect

3. The impact of power quality problems

power quality has great harm, which is mainly reflected in the following four aspects:

personal safety: first of all, it may cause harm to personal safety. For example, when a large-scale event is held, there is a voltage dip event, and there is no corresponding response measures, it may cause lighting problems, and then cause panic, stampede and other mass events. For special users such as hospitals, if a power failure occurs during the operation, it will be fatal to the patients

electrical safety: voltage sag, three-phase imbalance or excessive reactive power will cause certain damage to electrical safety

economic loss: for example, in 2016, Samsung transformer factory claimed that the loss was as high as 2billion US dollars due to the transformer fire, which affected the accuracy of indication

political impact: for example, power supply interruption or power accident during the Olympic Games or important meetings will bring serious political impact

II. Users' differentiated demand for power quality

1. Equipment sensitivity to power quality problems (taking voltage sag as an example)

taking voltage sag as an example, because voltage sag is the most serious power quality problem and the event causing the greatest loss

computers or power electronic equipment are sensitive to power quality. Because these aspects are widely used, people at home and abroad have conducted special research on them

for lighting equipment, take sodium lamp as an example. When the voltage amplitude is lower than 66%-84% and the duration is longer than MS, the sodium lamp will go out. It will not be started within dozens of minutes or even half an hour after going out, which will have a great impact. Because sodium lamps are often used in large venues, conference centers and other places, losing lighting is likely to cause stampede panic and other events

there is also medical equipment. The more sophisticated medical equipment requires higher power quality

2. Users' sensitivity to power quality issues (taking voltage sag as an example)

performance/sports venues are mainly sensitive to power quality issues in terms of lamps, security, security, etc

the data center is the most important load. Generally, it is equipped with ups and other power support equipment, but there are also contingencies. For example, during the rainy season in 2016, a data company in Yizhuang, Beijing, experienced a power outage, which directly led to the stagnation of data services such as Ping An insurance for half a day. Fortunately, the data was backed up and not lost

the communication industry is similar to the data center. On the one hand, it may cause data loss, on the other hand, it may cause communication interruption. If power quality problems occur in a specific area, resulting in power supply interruption, the communication of the whole area may be affected

3. Loss of power quality problems (taking voltage sag as an example)

if a bulb is damaged due to power quality problems, people generally don't care. What they really care about is that power quality problems have brought great losses to enterprises and users. The above table is summarized by foreign counterparts. Of course, it is not very accurate. Individual cases will have much more losses than those in the table, and some may not reach this loss. The statistics here mainly include the textile industry, plastic industry, glass processing industry, paper industry, steel enterprises and semiconductor manufacturing industry. The semiconductor manufacturing industry pays the most attention to the power quality problem because the power quality has the greatest loss to this industry

4. User classification

because different users have different requirements for power quality, user classification is very important for power quality services. The above form will be

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