CN106208081A - A kind of power regulation transmission system of band branch resistance - Google Patents

Abstract

The invention discloses a power regulation and transmission system with branch resistance, which comprises: an AC power controllable unit and an AC power natural control unit. The natural AC power control unit includes a first step-down transformer and a switch. The AC power controllable unit includes a rectifier and an inverter branch unit, and the inverter branch unit includes a branch resistor, an inverter and a second step-down transformer. This system loads the AC power controllable unit with DC resistance and branch resistance between the high-voltage bus and the transmission line, and uses the AC power controllable unit and the AC power natural control unit to realize the mutual interaction between the natural flow transmission of electric energy and the active power regulation. spare. When the AC power natural control unit is controlled separately, the transmission line outputs power according to the size of the line and load impedance to form natural power; when the AC power controllable unit is controlled separately, the method of constant current, constant voltage and constant power can be used to control The size of the output power of the transmission line forms a controllable power.

Description

A Power Regulating Transmission System with Branch Resistors

technical field

The invention relates to the technical field of electric power, in particular to a power regulation and control transmission system with branch resistors.

Background technique

In traditional 110kV, 220kV, 500kV and other high-voltage and ultra-high-voltage AC power transmission systems, the opening and disconnection of transmission lines are generally controlled by an AC circuit breaker 100 , as shown in FIG. 1 . The output power of the transmission line is distributed according to the natural flow, and is determined by the line impedance and load parameters. It is difficult to control the transmission power of the transmission line in real time through the mechanical AC circuit breaker 100 .

In modern power systems, AC and DC hybrid transmission technology is used. The principle of direct current transmission is to convert alternating current into direct current through a rectifier device, and then convert the direct current into alternating current through an inverter device after a transmission line of hundreds of kilometers or longer. Although this method solves the shortcomings of the traditional power transmission system, in practical applications, a power controllable power transmission system may be required in one case, but power controllable is not required in another case, that is, power is naturally controlled. It can be seen that the power transmission system in this mode has a single function, and when any hardware device in the power transmission system is damaged, the entire power transmission system will malfunction and the reliability is low.

It can be seen that how to improve the shortcoming of the single function of the power transmission system and how to improve the reliability of the power transmission system is an urgent problem to be solved by those skilled in the art.

Contents of the invention

The purpose of the present invention is to provide a power regulation and control transmission system with branch resistors, which is used to improve the shortcoming of the single function of the power transmission system and improve the reliability of the power transmission system.

In order to solve the above technical problems, the present invention provides a power regulation and control transmission system with branch resistors, including: an AC power controllable unit and an AC power natural control unit; the AC power natural control unit includes a high-voltage bus and a low-voltage bus The first step-down transformer between them is a switch arranged between the low-voltage busbar and the line-side busbar; the AC power controllable unit includes a rectifier and an inverter branch unit, and the inverter branch unit includes a branch resistor, an inverter A converter and a second step-down transformer, the first end of the rectifier is connected to the high-voltage bus, the second end of the rectifier is connected to the DC bus, and the third end of the rectifier is connected to the inverter The third end of the branch resistance is connected to the DC bus, the second end of the branch resistance is connected to the first end of the inverter, and the second end of the inverter connected to the first end of the second step-down transformer, and the second end of the second step-down transformer is connected to the line-side bus bar;

Wherein, the line-side bus bar is connected to the power transmission line.

Preferably, when the number of the transmission lines is greater than 1, the number of inverter branch units and the number of switches in the AC power controllable unit are the same as the number of the transmission lines, and the The number of the rectifier and the number of the first step-down transformer are one.

Preferably, the rectifier is a full bridge rectifier.

Preferably, the rectifier is a thyristor rectifier.

Preferably, the inverter is a full bridge inverter.

Preferably, the inverter is a sine wave inverter.

Preferably, the switch is a knife switch.

Preferably, the switch is an automatic switch.

Preferably, the switch is an AC circuit breaker.

The power regulation and control transmission system with branch resistance provided by the present invention loads the AC power controllable unit with DC resistance and branch resistance between the high-voltage bus and the transmission line, and utilizes the AC power controllable unit and the AC power natural control unit Realize the natural flow transmission of electric energy and active power regulation as backup for each other. When the AC power natural control unit operates and controls alone, the transmission line outputs power according to the size of the line and load impedance to form natural power; when the AC power controllable unit operates alone, the control method of constant current, constant voltage and constant power is adopted , can control the size of the output power of the transmission line to form a controllable power.

Description of drawings

In order to illustrate the embodiments of the present invention more clearly, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. As far as people are concerned, other drawings can also be obtained based on these drawings on the premise of not paying creative work.

FIG. 1 is a structural diagram of a power transmission control system in the prior art;

Fig. 2 is a structural diagram of a power regulation and control transmission system with branch resistors provided by an embodiment of the present invention;

Fig. 3 is an equivalent circuit diagram corresponding to an AC power controllable unit provided by the present invention;

The reference signs are as follows:

AC circuit breaker 100, AC power controllable unit 200, AC power natural control unit 300, high voltage bus 9, low voltage bus 1, first step-down transformer 2, line side bus 8, switch 7, rectifier 3, branch resistor 4, inverter Transformer 5, second step-down transformer 6, DC bus 11.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The core of the invention is to provide a power regulation and control transmission system with branch resistors.

In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Fig. 2 is a structural diagram of a power regulation transmission system with branch resistors provided by an embodiment of the present invention. As shown in Figure 2, the power regulation and transmission system with branch resistors includes: an AC power controllable unit 200 and an AC power natural control unit 300; the AC power natural control unit 300 includes a The first step-down transformer 2, the switch 7 arranged between the low-voltage bus 2 and the line-side bus 8; the AC power controllable unit 200 includes a rectifier 3 and an inverter branch unit, and the inverter branch unit includes a branch resistor 4, an inverter 5 and the second step-down transformer 6, the first end of the rectifier 3 is connected to the high voltage bus 9, the second end of the rectifier 3 is connected to the DC bus 11, the third end of the rectifier 3 is connected to the third end of the inverter 5, The first end of the branch resistor 4 is connected to the DC bus 11, the second end of the branch resistor 4 is connected to the first end of the inverter 5, the second end of the inverter 5 is connected to the first end of the second step-down transformer 6 connected, the second end of the second step-down transformer 6 is connected to the line side bus 8;

Wherein, the busbar 8 on the line side is connected to the transmission line 10 .

It should be noted that the AC power controllable in the AC power controllable unit 200 means that the AC power output can be controlled, and the AC power natural control in the AC power natural control unit 300 means that the AC power output cannot be controlled. the meaning of. The AC power controllable unit 200 and the AC power natural control unit 300 in the present invention are just names, which are for the purpose of distinction and have no other limiting meanings. In addition, a plurality of inverter branch units are shown in FIG. 2 , and each of the plurality of inverter branch units is connected to one rectifier 3 . It can be understood that there may be more than one rectifier 3 in FIG. 2 . For clarity of illustration, the dotted line box in FIG. 2 only marks one of the AC power controllable units 200 and one AC power natural control unit 300 , and the others are not marked.

In order to make those skilled in the art more aware of how the control system in the present invention is regulated, the calculation process of the electric energy parameters in the low-voltage transmission line corresponding to the AC power controllable unit 200 is given below.

FIG. 3 is obtained by simplifying the AC power controllable unit 200 in FIG. 2 . FIG. 3 is an equivalent circuit diagram corresponding to an AC power controllable unit provided by the present invention.

In the simplified DC unit shown in Figure 3, the DC voltage and DC current on the DC side of the rectifier 3 and inverter 5 are respectively:

E _dr ＝K ₀ (E _r cosα-X _r )-R _r I _d (1)

E _di ＝K ₀ (E _i cosβ+X _i +X _L )+(R _i +R _L )I _d (2)

${\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; i</span>}}}{\mathrm{<span\; class="notranslate">\; R</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Among them, _{K 0} is a coefficient determined by the connection mode of the rectifier circuit, R _r and R _i are the resistances corresponding to the losses of the rectifier 3 and the inverter 5 respectively, R is the resistance of the branch DC resistance 4, ID is the DC current, E _dr , E _di are the DC side DC voltages of the rectifier 3 and the inverter 5 respectively, E _r , E _i are the root mean square values of the AC voltages of the rectifier 3 and the inverter 5 respectively, X _r , _Xi are the rectifier 3 , the commutation reactance of the inverter 5, α and β are the firing angles of the rectifier 3 and the inverter 5 respectively, and R _i and _RL are the resistance and reactance of the transmission line 10 respectively.

Each transmission line 10 is regulated by being equipped with multiple low-voltage line active power control systems with DC resistance and branch resistance, so that the AC power controllable unit 200 and the AC power natural control unit 300 can be switched and operated as backup for each other. The DC unit goes through the "rectification-inversion" process within a short distance, and uses the principle of DC transmission to realize the artificial control of the output power of the 380V low-voltage transmission line and realize the real-time control of the active power of the AC transmission system.

The operation of each transmission line 10 under the control of the AC power controllable unit 200 will affect the total DC resistance, and further affect the total DC current output by the rectifier 3 , and finally affect the DC current of each transmission line 10 ie power. That is to say, the operation of each transmission line 10 under the control of the AC power controllable unit 200 affects each other, and coordinated control must be carried out to achieve stable power output.

When the power transmission line 10 is running under the control of the natural AC power control unit 300, the electric energy of the low-voltage bus 1 is obtained directly, and power control cannot be performed.

The power regulation and control transmission system with branch resistance provided in this embodiment, by loading the AC power controllable unit with DC resistance and branch resistance between the high-voltage bus and the transmission line, uses the AC power controllable unit and the AC power natural control unit Realize the natural flow transmission of electric energy and active power regulation as backup for each other. When the AC power natural control unit operates and controls alone, the transmission line outputs power according to the size of the line and load impedance to form natural power; when the AC power controllable unit operates alone, the control method of constant current, constant voltage and constant power is adopted , can control the size of the output power of the transmission line to form a controllable power.

It can be understood that FIG. 2 is only a specific application scenario, and the number of AC power controllable units 200 and AC power natural control units 300 needs to be selected according to actual conditions.

As a preferred embodiment, when the number of transmission lines 10 is greater than 1, the number of inverter branch units and the number of switches 7 in the AC power controllable unit 200 are the same as the number of transmission lines 10, and the rectifier 3 and the number of the first step-down transformer 2 is one.

It can be understood that, in the above case, the number of rectifiers 3 can also be set to be multiple to facilitate one-to-one correspondence of the transmission lines 10, but, considering issues such as power consumption, only one rectifier 3 is selected here.

As a preferred embodiment, the rectifier 3 is a full bridge rectifier. It can be understood that the rectifier 3 can be of various types. For example, in addition to the full-bridge rectifier in the bridge rectifier, it can also be a half-bridge rectifier.

As a preferred embodiment, the rectifier 3 is a thyristor rectifier. It can be understood that the rectifier 3 can be of various types, for example, besides a thyristor rectifier, it can also be a diode rectifier. However, in consideration of practical applications, a thyristor rectifier is used in the present invention.

As a preferred embodiment, the inverter is a full-bridge inverter. It can be understood that, besides being a full-bridge inverter, the inverter 5 may also be a half-bridge inverter, and this is only a specific implementation manner.

As a preferred embodiment, the inverter 5 is a sine wave inverter. The output signal of the sine wave inverter can be converted directly using wireless.

As a preferred embodiment, the switch 7 is a knife switch.

As a preferred embodiment, the switch 7 is an automatic switch. The automatic switch can also switch on and off the circuit infrequently and control the motor to start directly. Therefore, the automatic switch is a commonly used breaking and closing device with a protection link for low-voltage circuits.

As a preferred embodiment, the switch 7 is an AC circuit breaker.

It can be understood that the function of the switch 7 is to realize the on-off of the electrical signal, therefore, there are many forms of the switch 7 and are not limited to the above implementation manners.

The power control transmission system with branch resistors provided by the present invention has been introduced in detail above. Each embodiment in the description is described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same and similar parts of each embodiment can be referred to each other. As for the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and for the related part, please refer to the description of the method part. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Professionals can further realize that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, computer software or a combination of the two. In order to clearly illustrate the possible For interchangeability, in the above description, the composition and steps of each example have been generally described according to their functions. Whether these functions are executed by hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be regarded as exceeding the scope of the present invention.

The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be directly implemented by hardware, software modules executed by a processor, or a combination of both. Software modules can be placed in random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other Any other known storage medium.

Claims (9)

1. the power regulation transmission system of a band branch resistance, it is characterised in that including: AC power controllable with exchange Power natural contral unit；Described AC power natural contral unit, including being arranged between high voltage bus and low-voltage bus bar First step-down transformer, is arranged at the switch between described low-voltage bus bar and line side bus；Described AC power controllable Including commutator and inversion branch units, described inversion branch units includes branch resistance, inverter and the second step-down transformer, First end of described commutator is connected with described high voltage bus, and the second end of described commutator is connected with described dc bus, institute Stating the 3rd end of commutator and the three-terminal link of described inverter, the first end of described branch resistance is with described dc bus even Connecing, the second end of described branch resistance is connected with the first end of described inverter, the second end of described inverter and described second First end of step-down transformer connects, and the second end of described second step-down transformer is connected with described line side bus；

Wherein, described line side bus is connected with transmission line of electricity.

The power regulation transmission system of band branch resistance the most according to claim 1, it is characterised in that when described power transmission line When the number on road is more than 1, the number of the inversion branch units in described AC power controllable and the number of described switch Identical with the number of described transmission line of electricity, and the quantity of the quantity of described commutator and described first step-down transformer is 1.

The power regulation transmission system of band branch resistance the most according to claim 1, it is characterised in that described commutator is Full-bridge rectifier.

The power regulation transmission system of band branch resistance the most according to claim 1, it is characterised in that described commutator is Silicon controlled rectifier.

The power regulation transmission system of band branch resistance the most according to claim 1, it is characterised in that described inverter is Full-bridge inverter.

The power regulation transmission system of band branch resistance the most according to claim 1, it is characterised in that described inverter is Sinewave inverter.

The power regulation transmission system of band branch resistance the most according to claim 1, it is characterised in that described switch is lock Knife-like switch.

The power regulation transmission system of band branch resistance the most according to claim 1, it is characterised in that described switch is certainly Dynamic switch.

The power regulation transmission system of band branch resistance the most according to claim 1, it is characterised in that described switch is for handing over Stream chopper.