CN110867859B - Real-time control method for solid-state circuit breaker - Google Patents

Real-time control method for solid-state circuit breaker Download PDF

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CN110867859B
CN110867859B CN201911202300.7A CN201911202300A CN110867859B CN 110867859 B CN110867859 B CN 110867859B CN 201911202300 A CN201911202300 A CN 201911202300A CN 110867859 B CN110867859 B CN 110867859B
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solid
circuit breaker
power
state circuit
control
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CN110867859A (en
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雷家兴
丁高峰
林鹤云
余鹏飞
孙开原
陈凯华
虞国荣
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Foretech Elec App Jiangsu Corp ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/008—Circuit arrangements for ac mains or ac distribution networks involving trading of energy or energy transmission rights

Abstract

The invention discloses a real-time control method of a solid-state circuit breaker, and belongs to the field of power distribution and utilization of a power system. The method comprises the modules of power grid voltage detection and current detection, power grid real-time frequency calculation, load accumulated electric energy calculation, period average power price calculation, related control factor calculation, comprehensive decision and control system and the like. The invention utilizes the characteristics that the solid-state circuit breaker can be switched on and off at high speed and the like, and comprehensively considers a plurality of factors such as circuit fault state, power grid frequency fluctuation, load power consumption demand and cost and the like, thereby realizing the active and real-time control of the solid-state circuit breaker. The invention not only improves the utilization efficiency of the solid-state circuit breaker, but also can realize the active demand response control technology, is beneficial to improving the frequency characteristic of a power grid, reducing the load electricity consumption cost and realizing the win-win of the power generation side and the electricity consumption side in a power system.

Description

Real-time control method for solid-state circuit breaker
Technical Field
The invention relates to the field of power distribution and power utilization, in particular to a real-time control method for a solid-state circuit breaker.
Background
The solid-state circuit breaker is mainly based on modern electronic technology, and the on-off control of a circuit is realized through a semiconductor device. Compared with the traditional mechanical circuit breaker, the solid-state circuit breaker has the advantages of no need of arc extinction, rapid on-off and the like, and is the main direction of intelligent and modern development of the circuit breaker. In recent years, with the large-scale access of new energy sources such as wind power and photovoltaic and the rapid development of micro-grids, the application demand of the solid-state circuit breaker is increased. Both the academic world and the industrial world at home and abroad have invested a great deal of research efforts in solid-state circuit breakers of different voltage and current classes. For example, the high-power electronic device factory in Marvin, USA manufactured a solid-state circuit breaker prototype of 15kV/600A in the 90 s of the past century; ABB, a well-known electrical appliance manufacturer also develops a solid-state circuit breaker prototype of a megawatt system; the solid-state circuit breaker of 6.6kV/400A is intensively researched by a power company of northeast China through a large number of experiments; research work on the aspects of topology, simulation, experimental technology and the like of the solid-state circuit breaker is also carried out by RPTH-Aachen university in Germany.
Solid state circuit breakers, while having significant advantages in technology and performance, have significant economic disadvantages. The cost of the semiconductor devices required for solid state circuit breakers is much higher than for conventional mechanical switches. In general application, if a traditional mechanical switch with price advantage is sufficient only for realizing the fault isolation and protection functions of a circuit, the solid-state circuit breaker does not have any practical place. Therefore, the low device utilization rate restricts the development progress of the solid-state circuit breaker. Fully exploiting and utilizing the functionality of solid state circuit breakers would be a necessary means to accelerate the development of their applications.
In recent years, demand response technology of power systems has received increasing attention. The demand response means that when the electricity price is increased or the system running state is threatened, the electricity load actively changes the electricity utilization mode (such as reducing electricity consumption in a peak period, increasing electricity consumption in a valley period and the like) so as to realize the functions of peak clipping, valley filling, peak shifting and valley shifting, thereby ensuring the stable running of the power grid. Obviously, the implementation of the demand response technology depends on the on-off control of the circuit, and the existing implementation method needs a power supply company or a user to send out a control instruction, so that the real-time performance and the initiative performance are relatively poor. Under the background, the solid-state circuit breaker which can be actively controlled, is high in breaking speed and rich in collected information plays a very positive role, and related research works are not reported in a public way.
Disclosure of Invention
The purpose of the invention is as follows: the invention aims to provide a real-time control method of a solid-state circuit breaker, which realizes active demand response control while providing fault protection so as to improve the device utilization rate of the solid-state circuit breaker.
In order to achieve the purpose, the invention adopts the following technical scheme:
a real-time control method for a solid-state circuit breaker comprises the following steps:
s1, obtaining the three-phase grid voltage u through the detection circuitgA、ugB、ugCAnd three-phase network current igA、igB、igC；
S2 passing through three-phase grid current igA、igB、igCCalculating a fault control factor k1；
S3, passing through three-phase grid voltage ugA、ugB、ugCCalculating the real-time frequency f of the power gridgAnd a frequency control factor k2；
S4 passing through three-phase grid current igA、igB、igCAnd three-phase network voltage ugA、ugB、ugCCalculating the accumulated electric energy W actually consumed by the loadLReference power value P required by loadL *Reference electric energy W for calculating loadL *From WLAnd WL *Calculating the electric energy control factor k3；
S5, according to time-of-use electricity price cPCalculating the average electricity price c of the periodAPFrom cPAnd cPLCalculating a power rate control factor k4；
S6, according to the control factor k1、k2、k3、k4Generating a comprehensive decision factor kTotalAnd through kTotalGenerating an opening control signal S for a solid state circuit breakerg。
Preferably, in step S2, the control factor k is1The calculation method comprises the following steps:
Figure BDA0002296170040000021
in the formula, MIFor the absolute value | i of the three-phase network currentgA|、|igB|、|igCThe maximum value of |; i isTHIs a preset current protection threshold.
Preferably, in step S3,
1) the power grid real timeFrequency fgCalculating by a three-phase voltage phase-locked loop algorithm;
2) the frequency control factor k2The calculation method comprises the following steps:
Figure BDA0002296170040000022
in the formula (f)g0Representing the reference frequency, k, of the power system21The weighting factor is controlled for a predetermined frequency.
Preferably, in step S4,
1) the accumulated electric energy W actually consumed by the loadLThe calculation method comprises the following steps:
Figure BDA0002296170040000023
in the formula, TTotalThe total running time of the system since starting is represented by t, which is an integral time variable;
2) reference electric energy W of the loadL *The calculation method comprises the following steps:
Figure BDA0002296170040000024
3) the electric energy control factor k3The calculation method comprises the following steps:
Figure BDA0002296170040000031
in the formula,. DELTA.WLIs a preset power tolerance.
Preferably, in step S5,
1) the period average electricity price cAPThe calculation method comprises the following steps:
Figure BDA0002296170040000032
in the formula, TcCalculating a period for electricity prices;
2) the electricity price control factor k4The calculation method comprises the following steps:
Figure BDA0002296170040000033
in the formula, k41The weight coefficient is controlled for the preset electricity price.
Preferably, in step S6,
1) integrated decision factor kTotalThe calculation method comprises the following steps:
kTotal＝k1·k2·k3·k4
2) on-off control signal SgThe generation method comprises the following steps: at each on-off control period T of the solid-state circuit breakerSTime T for conduction of internal and solid-state circuit breakersonComprises the following steps:
Ton＝TS·kTotal·DNorm
in the formula, DNormThe time proportion of the normal operation of the load is; at each on-off control period TSFront T ofonWithin the time, the solid-state circuit breaker is conducted; remaining T in each on-off control periodS-TonDuring time, the solid state circuit breaker is off.
Compared with the prior art, the invention has the beneficial effects that:
the real-time control method of the solid-state circuit breaker disclosed by the invention does not need to add an additional hardware circuit, and has the following beneficial effects through the improvement of a control system:
(1) the circuit breaker has multiple purposes, not only provides a fault protection function, but also can realize active demand response control, and improves the utilization efficiency of the device.
(2) The real-time control of the circuit breaker can realize the functions of peak clipping, valley filling, peak shifting and valley shifting, and is beneficial to keeping the safe and stable operation of a power grid;
(3) the real-time control of the circuit breaker can also reduce the power consumption when the electricity price is higher, and increase the power consumption when the electricity price is lower, thereby improving the electricity economy of the user and increasing the profit of the user.
Drawings
Fig. 1 is a schematic diagram of a real-time control method of a solid-state circuit breaker according to the present invention;
FIG. 2 shows a fault control factor k1Generating a schematic diagram;
FIG. 3 shows the frequency control factor k2Generating a schematic diagram;
FIG. 4 shows the power control factor k3Generating a schematic diagram;
FIG. 5 shows the power rate control factor k4Generating a schematic diagram;
fig. 6 is a schematic diagram of the periodic control of the solid-state circuit breaker.
Detailed Description
The technical solution of the present invention will be further described with reference to the following detailed description and accompanying drawings. Fig. 1 is a schematic diagram of a control method of the present invention, which includes modules such as voltage detection, current detection, fault control factor calculation, grid real-time frequency calculation, frequency control factor calculation, load accumulated power calculation, power control factor calculation, cycle average power price calculation, power price control factor calculation, and comprehensive decision and control system. Specific data will be described as an example of a specific embodiment of the present invention.
Fault protection is the primary function of a solid state circuit breaker, and therefore it is necessary to first determine whether an overcurrent signal is present in the circuit. When the three-phase current i is as shown in FIG. 2gA、igB、igCAny phase current is larger than a set threshold value ITHOr less than-ITHWhen the solid-state circuit breakers are all turned off, the fault control factor k can be used1And 0 represents. When the three-phase current is not in fault, the factor k is controlled1I.e. 1, indicates that the subsequent control function is not affected. I.e. k1The expression of (a) is:
Figure BDA0002296170040000041
wherein M isI＝max(|igA|,|igB|,|igC|)
In the formula, max represents a function of taking the maximum value.
In addition to being useful for fault protection, circuit breakers can also achieve frequency modulation in other situations. As shown in fig. 3, according to the three-phase system voltage ugA、ugB、ugCThe real-time frequency f of the power grid can be calculated by adopting a phase-locked loop algorithmg. When f isgGreater than the system reference frequency fg0The active power surplus of the current power system is represented, and at the moment, the load can absorb more active power to assist in maintaining stable frequency; when f isgIs less than fg0When the active power of the current power system is insufficient, the load can reduce the active power consumption to assist in maintaining the stable frequency. Setting a frequency control factor k2Comprises the following steps:
Figure BDA0002296170040000042
in the formula, k21The weight coefficient for frequency control can be set in advance according to the importance of frequency control, k21Setting to 0 indicates that the solid state breaker is not involved in frequency control, k21The larger the solid state circuit breaker, the greater the degree to which it participates in system frequency control.
Furthermore, the control of the solid-state circuit breaker should also meet the demand for electrical energy consumption for the load. Firstly, the instantaneous power consumed by the load can be calculated according to the power grid and the voltage as follows:
Figure BDA0002296170040000051
for loads that can participate in demand response control, their instantaneous power p is not requiredLAnd its expected value PL *Similarly, as long as the power it absorbs is maintained near the desired power. Therefore, first, the cumulative electric energy W actually consumed by the load is calculatedL：
Figure BDA0002296170040000052
In the formula, TTotalThe total running time since the system is started, and t is an integration time variable. In actual operation, the accumulated electric energy can be periodically cleared according to needs. Similarly, the reference electric energy W required by the load can be calculatedL *：
Figure BDA0002296170040000053
As long as WLIs maintained at WL *And nearby, the situation that the electric energy absorbed by the load meets the requirement can be shown. Thus, the power control factor k of the load may be defined3Comprises the following steps:
Figure BDA0002296170040000054
in the formula,. DELTA.WLIs a preset power tolerance. At WL *-ΔWL＜WL＜WL *+ΔWLIn the range of k3A value of 1 indicates that the power control of the load maintains the current state. When W isL≥WL *+ΔWLWhen the load is in a state of being out of a state of being in a state of being out of a state of being in a state of being actually absorbed by the load; when W isL≤WL *+ΔWLAt the moment, the electric energy actually needed by the load is lower than the requirement, and at the moment, the electric energy transmission needs to be increased through the control of the solid-state circuit breaker. Electric energy control factor k3The resulting schematic is shown in fig. 4.
Real-time control of the solid state circuit breaker should also take into account current grid electricity price levels. Obviously, when the price of electricity is high, the load should reduce the consumption of electric energy; and when the electricity price is low, the load can increase the power consumption. To characterize this behavior, a power rate calculation period T is first definedCInternal, real-time electricity price cPHas an average value of cAPI.e. cAPSatisfies the following conditions:
Figure BDA0002296170040000055
calculating the period TCMay be defined in terms of a statistical period and may be a day, a week, a month or other time. The electricity rate control factor k can then be defined4：
Figure BDA0002296170040000061
In the formula, k41The weight coefficient is controlled for the preset electricity price. k is a radical of41The larger the electricity price means the more the real-time control of the solid-state circuit breaker is affected, k41A value of 0 means that the electricity price does not affect at all. FIG. 5 shows the power rate control factor k4Can be seen that k is the higher the price of electricity4Smaller, when the price of electricity is lower, k4It is larger.
The four control factors jointly determine the conduction state of the solid-state circuit breaker, and a comprehensive decision factor k is definedTotalIs the product of four control factors, i.e.
kTotal＝k1·k2·k3·k4
As described above, the fault control factor k1Is 0 when overcurrent or short-circuit fault occurs, and k is equal to the value of the other factorsTotalAre all 0, this time indicating that the solid state breaker is fully off. Therefore, the control method of the invention does not influence the fault protection function of the circuit. According to kTotalThe time T for the conduction of the solid-state circuit breaker can be further definedonComprises the following steps:
Ton＝TS·kTotal·DNorm
in the formula, TSFor the on-off control period of solid-state circuit breakers, DNormIs the time proportion of the normal operation of the load. If the average daily operating time of a certain load is 18 hours, DNormIs 0.75. T issCan be comprehensively set according to factors such as the control speed of the solid-state circuit breaker, the sensitivity of the load to the on-off control and the like, and can be set to be 1 hourAnd (4) equivalence. At the obtaining of TonAfter a parameter, the solid-state breaker is generated at time TSInternal control signal SgAs shown in fig. 6. At TSFirst T of cycleonWithin time, SgThe high level indicates that the solid-state circuit breaker is in a conducting state; during the rest of the time, SgA low level indicates that the solid state breaker is in an off state.
The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose of the embodiments is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All modifications made according to the spirit of the main technical scheme of the invention are covered in the protection scope of the invention.

Claims (1)

1. A real-time control method for a solid-state circuit breaker is characterized by comprising the following steps:
s1, obtaining the three-phase grid voltage u through the detection circuitgA、ugB、ugCAnd three-phase network current igA、igB、igC；
S2 passing through three-phase grid current igA、igB、igCCalculating a fault control factor k1；
The control factor k1The calculation method comprises the following steps:
Figure FDA0003425271510000011
in the formula, MIFor the absolute value | i of the three-phase network currentgA|、|igB|、|igCThe maximum value of |; i isTHA preset current protection threshold value;
s3, passing through three-phase grid voltage ugA、ugB、ugCCalculating the real-time frequency f of the power gridgAnd a frequency control factor k2；
1) The real-time frequency f of the power gridgCalculating by a three-phase voltage phase-locked loop algorithm;
2) the frequency control factor k2The calculation method comprises the following steps:
Figure FDA0003425271510000012
in the formula (f)g0Representing the reference frequency, k, of the power system21Controlling a weight coefficient for a preset frequency;
s4 passing through three-phase grid current igA、igB、igCAnd three-phase network voltage ugA、ugB、ugCCalculating the accumulated electric energy W actually consumed by the loadLReference power value P required by loadL *Reference electric energy W for calculating loadL *From WLAnd WL *Calculating the electric energy control factor k3；
1) The accumulated electric energy W actually consumed by the loadLThe calculation method comprises the following steps:
Figure FDA0003425271510000013
in the formula, TTotalThe total running time of the system since starting is represented by t, which is an integral time variable;
2) reference electric energy W of the loadL *The calculation method comprises the following steps:
Figure FDA0003425271510000014
3) the electric energy control factor k3The calculation method comprises the following steps:
Figure FDA0003425271510000021
in the formula, Delta WLFor a predetermined allowable deviation of electric energyA difference;
s5, according to time-of-use electricity price cPCalculating the average electricity price c of the periodAPFrom cPAnd cAPCalculating a power rate control factor k4；
1) The period average electricity price cAPThe calculation method comprises the following steps:
Figure FDA0003425271510000022
in the formula, TcCalculating a period for electricity prices;
2) the calculation method of the electricity price control factor k4 comprises the following steps:
Figure FDA0003425271510000023
in the formula, k41Controlling a weight coefficient for a preset electricity price;
s6, according to the control factor k1、k2、k3、k4Generating a comprehensive decision factor kTotalAnd through kTotalGenerating an opening control signal S for a solid state circuit breakerg，
1) Integrated decision factor kTotalThe calculation method comprises the following steps:
kTotal＝k1·k2·k3·k4
2) on-off control signal SgThe generation method comprises the following steps: at each on-off control period T of the solid-state circuit breakerSTime T for conduction of internal and solid-state circuit breakersonComprises the following steps:
Ton＝TS·kTotal·DNorm。
in the formula, DNormThe time proportion of the normal operation of the load is; at each on-off control period TSFront T ofonWithin the time, the solid-state circuit breaker is conducted; remaining T in each on-off control periodS-TonDuring time, the solid state circuit breaker is off.
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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108964276A (en) * 2018-07-16 2018-12-07 河南理工大学 Support the electricity consumption control terminal and system and load discrimination method of automatic demand response

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US10630069B2 (en) * 2017-10-03 2020-04-21 Atom Power, Inc. Solid-state circuit interrupter and arc inhibitor

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108964276A (en) * 2018-07-16 2018-12-07 河南理工大学 Support the electricity consumption control terminal and system and load discrimination method of automatic demand response

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"直流固态断路器现状及应用前景";胡杰等;《电力系统保护与控制》;20091001;全文 *

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