Distribution network computing power

1. (1) The network topology is obtained by analyzing the connection relationship of the equipment with the matrix representation of the incidence table, the matrix of the incidence table and the number of the equipment. There are two table matrices, the node description matrix with n rows and 13 columns and the branch description matrix with M rows and 16 columns
(2) net based matrix representation: this method is based on graph theory. The basic idea is: the distribution network is a variable structure network, which is composed of nodes and arcs
(3) node elimination method: this method reces the order of adjacency matrix, reces the amount of calculation and rendancy, and improves the speed of calculation by eliminating intermediate nodes. And Xiangtai electric suggests that the basic idea of this algorithm is to ignore the intermediate nodes and only analyze the connectivity between nodes that have an important impact on the topology
(4) tree search method: in tree search, the bus is regarded as the vertex of the graph, and the branch is regarded as the edge of the graph. Generally speaking, it is rare for the distribution network to change the network structure greatly e to the switch displacement
(5) discrete processing method: the power system contains both continuous and discrete dynamics. It is a typical discrete event dynamic process that the change of switching state causes the change of power system network structure.

2.

Distribution network refers to the power network that receives electric energy from the transmission network or regional power plants and distributes it to various users locally or step by step according to voltage through distribution facilities

the system from the step-down distribution substation (high-voltage distribution substation) to the user end is called distribution system. Power distribution system is a power network system composed of a variety of power distribution equipment (or components) and distribution facilities, which transforms voltage and distributes electric energy directly to end users

distribution network is composed of overhead lines, towers, cables, distribution transformers, switchgear, reactive compensation capacitors and other distribution equipment and ancillary facilities. Its main role in the power network is to distribute electric energy. From the point of view of the nature of the distribution network, the distribution network equipment also includes the distribution equipment of the substation

extended data:

classification

1. According to voltage level classification

distribution network can be divided into: high voltage distribution network (6 ~ 110kV); Low voltage distribution network (0.4kV)

According to the classification of power supply area, the distribution network can be divided into: urban distribution network; Rural distribution network; Plant distribution network

The distribution network can be divided into: main network (66kV and above); Distribution network (35kV and below)

3. A power network that receives electric energy from a transmission network or a regional power plant and distributes it locally or step by step according to voltage to various users through distribution facilities
distribution network is composed of overhead lines, cables, towers, distribution transformers, disconnectors, reactive power compensation capacitors and some ancillary facilities
distribution network can be divided into high voltage distribution network (35-110kv), medium voltage distribution network (6-10KV, 20kV in Suzhou) and low voltage distribution network (220 / 380V)
in mega cities with large load rate, 220kV power grid also has distribution function
according to the function of power supply area, it can be divided into urban distribution network, rural distribution network and factory distribution network
in the urban power grid system, the main network refers to the power grid with voltage level of 110kV and above, which is mainly used to connect the regional high-voltage (220kV and above) power grid
the distribution network refers to the power grid with voltage level of 35kV and below, which is used to supply power to various distribution stations and various electrical loads in the city

4. Active distribution network is a system composed of micro power supply, load, energy storage system and control devices
2. Traditional distribution network is passive, and its operation, control and management mode are passive. The power proced by large power plants flows through the transmission network (high voltage) and is sent to users through the distribution network (MV and LV). Therefore, the medium and low voltage (LV) distribution network is the "passive" load of the power system, so the distribution network can be called passive distribution network (PDN). Even if distribution automation is adopted, especially in China, its core control idea is still passive, that is, in the case of no fault, automatic control operation is generally not carried out. The existing distribution network analysis and calculation, regardless of loss, voltage and reliability, are based on the maximum load condition or average load condition. Therefore, the traditional distribution system is not designed to access a large number of distributed resources. A large number of distributed energy (DER) connected to the distribution network may bring many impacts. For example, it affects short circuit level and equipment selection, reactive power and voltage distribution, protection, distribution automation and fault clearing process, and island operation under special conditions. Therefore, in order to deal with the access of a large number of distributed der and maintain the original reliability, it needs to develop to active control and active management.

5. The former is mainly responsible for the task of regional power transmission, characterized by long distance, large capacity and wide power supply range, which determines that it is high voltage (usually ultra-high voltage or ultra-high voltage), and a certain proportion of it may be DC. It's like an artery coming directly from the heart
the latter is responsible for power supply for specific loads (users), with short distance, small capacity, low voltage (generally 35kV and below), and specific users. There is also the analogy of the human blood system, which is equivalent to the capillaries at the end
the difference in operation is not very big. The major principles are safety, qualified voltage quality, continuous and reliable power supply, etc. However, e to different load characteristics, there are still some differences. The performance is as follows: 1. The characteristics of load curve are different, the distribution changes much and violently, the reactive power compensation equipment with it is more frequent, and the switching operation is more. 2. The distribution network users are clear that they can mainly guarantee the important users and generally treat or even not guarantee the secondary users. However, the transmission network has more users and may (generally) contain important or even extremely important users, so it has higher requirements on the reliability of power supply, especially now the new electric power investigation regulations have been implemented, When the loss load reaches a certain proportion, it is also an accident, and the corresponding requirements for equipment and operation are higher. 3. In order to increase the sales of electricity, it is generally arranged according to the maintenance of power generation equipment in power plants, while in the distribution system, it is more arranged according to the equipment outage or maintenance of large users.

6.

1、 Different definitions
transmission network is the power transmission network connecting power plants, substations or substations

distribution network refers to the power network that receives electric energy from the transmission network or regional power plants and distributes it to various users locally or step by step according to voltage through distribution facilities

Second, different purposes:

transmission network mainly undertakes the task of transmitting electric energy

distribution network is to undertake the task of distribution, which is distributed to all kinds of users by distribution facilities or voltage level by level

According to the different transmission voltage, the transmission network can be divided into:

1, high voltage transmission network (110 ~ 220kV)

2, ultra high voltage transmission network (330 ~ 750kV)

3, ultra high voltage transmission network (1000kV and above)

distribution network:

1. According to the voltage level, it can be divided into: high voltage distribution network (6 ~ 110kV); Low voltage distribution network (0.4kV)

According to the classification of power supply area, distribution network can be divided into: urban distribution network; Rural distribution network; Plant distribution network

According to the function of power grid, distribution network can be divided into main network (66kV and above); Distribution network (35kV and below)

Four: different composition:

transmission network is composed of transmission equipment and substation equipment. Transmission equipment mainly includes transmission lines, towers, insulator strings, empty lines, etc; Substation equipment mainly includes transformer, reactor, capacitor, circuit breaker, grounding switch, lightning arrester, voltage transformer, current transformer and power protection, monitoring, control and communication system

distribution network is composed of overhead lines, cables, towers, distribution transformers, disconnectors, reactive power compensators and some ancillary facilities, which plays an important role in the distribution of electric energy in the power network

Other aspects:

the basic connection modes of transmission network can be divided into four types: no standby open connection mode, standby open connection mode, simple closed connection mode and complex closed connection mode

distribution network generally adopts closed-loop design and open-loop operation, and its structure is radial. The closed-loop structure is adopted to improve the flexibility of operation and reliability of power supply; On the one hand, the open-loop operation is to limit the short-circuit fault current and prevent the explosion of the circuit breaker beyond the breaking capacity; on the other hand, it is to control the fault spread range and avoid the expansion of the fault outage range

7. Transmission network is a power network that connects power plant and substation, substation and substation through high-voltage and ultra-high voltage transmission lines to complete power transmission. It is also known as the main grid in power network. Distribution network is a kind of power network that receives electric energy from transmission network or regional power plants and distributes it to users locally or step by step through distribution facilities.

8. Distribution network
generally refers to distribution network
electric energy network
with two meanings
distribution network is composed of overhead lines, cables, towers, distribution transformers, disconnectors, reactive power compensators and some ancillary facilities, The distribution network, which plays an important role in power distribution, can be divided into high voltage distribution network (35-110kv), medium voltage distribution network (6-10KV, 20kV in Suzhou) and low voltage distribution network (220 / 380V)

in large cities with large load rate, 220kV power grid also has distribution function< According to the function of power supply area, it can be divided into urban distribution network, rural distribution network and factory distribution network<

in the urban power grid system, the main network refers to the power grid with voltage level of 110kV or above, which is mainly used to connect the regional high-voltage (220kV or above) power grid

the distribution network refers to the power grid with voltage level of 35kV or below, which is used to supply power to various distribution stations and various electrical loads in the city

the distribution network generally adopts closed-loop design and open-loop operation, Its structure is radial. The diameter of distribution line is smaller than that of transmission line, which leads to a larger distribution network. Due to the complexity of distribution lines, it is difficult to guarantee the convergence of these algorithms in power flow calculation of distribution network.

9. Distribution network refers to the power supply network to the load area below 220kV, including distribution substation, switching station, cable and overhead lines and other primary systems; The power distribution system is more complex, in addition to the above, it also includes all the secondary equipment, as well as the processing software system involved in the power system