阅读说明：本技术 一种低压智慧断路器保护方法及系统 (Low-voltage intelligent circuit breaker protection method and system ) 是由 汪泓 黄悦华 汪超杰 于 2021-06-07 设计创作，主要内容包括：本发明涉及一种低压智慧断路器保护方法及系统,所述方法包括以下步骤：获取配电网漏电电流值及单位时间内漏电电流变化量；确定漏电电流阈值和电流变化量阈值,将所述漏电电流阈值和电流变化量阈值下发；根据配电网漏电电流值、单位时间内漏电电流变化量、漏电电流阈值和电流变化量阈值,确定是否进行断路保护。本发明提供的低压智慧断路器保护方法,可以有效防止漏电保护器的误动。(The invention relates to a method and a system for protecting a low-voltage intelligent circuit breaker, wherein the method comprises the following steps: acquiring the leakage current value of the power distribution network and the leakage current variable quantity in unit time; determining a leakage current threshold value and a current variation threshold value, and issuing the leakage current threshold value and the current variation threshold value; and determining whether to perform open circuit protection according to the leakage current value of the power distribution network, the leakage current variation in unit time, the leakage current threshold and the current variation threshold. The protection method of the intelligent low-voltage circuit breaker can effectively prevent the misoperation of the leakage protector.)

1. A protection method for a low-voltage intelligent circuit breaker is characterized by comprising the following steps:

acquiring the leakage current value of the power distribution network and the leakage current variable quantity in unit time;

determining a leakage current threshold value and a current variation threshold value, and issuing the leakage current threshold value and the current variation threshold value;

and determining whether to perform open circuit protection according to the leakage current value of the power distribution network, the leakage current variation in unit time, the leakage current threshold and the current variation threshold.

2. The method according to claim 1, wherein the determining whether to perform the open circuit protection according to the distribution network leakage current value, the leakage current variation in unit time, the leakage current threshold and the current variation threshold specifically comprises: and if the leakage current value of the power distribution network is greater than the leakage current threshold value and lasts for a set time length, or the leakage current variation in unit time is greater than the current variation threshold value, performing open circuit protection, otherwise, not performing open circuit protection.

3. The method according to claim 1, wherein the determining of the leakage current threshold specifically comprises: and measuring the current average value of the electric leakage of the power distribution network, taking the current average value of the electric leakage of the power distribution network as a current reference value, and determining an electric leakage current threshold value according to the current reference value.

4. The method according to claim 3, wherein determining the leakage current threshold according to the current reference value specifically comprises: and subtracting the current reference value from the sequence of the leakage current to obtain a residual sequence, acquiring the standard deviation of the residual sequence, and taking the sum of the reference value and the standard deviation of the multiple residual sequence as the leakage current threshold value.

5. The method according to claim 1, wherein the determining the leakage current threshold specifically includes obtaining a ratio between the load current and the leakage current at different times, obtaining a moving average value according to the ratio between the load current and the leakage current at different times, obtaining a residual sequence according to the moving average value, a theoretical value of the leakage circuit, and a sequence of the leakage current, obtaining a standard deviation of the residual sequence, and taking a sum of a reference value and a standard deviation of a multiple of the residual sequence as the leakage current threshold.

6. The method according to claim 5, wherein the determining of the leakage current threshold includes: and acquiring a history coefficient, an environment coefficient and a maximum value of the leakage current, and determining a leakage current threshold according to the history coefficient, the environment coefficient and the maximum value of the leakage current.

7. The method according to claim 6, wherein the determining a threshold value for the amount of current change specifically comprises: the determining of the current variation threshold specifically includes: and obtaining a leakage current difference history coefficient, an environment coefficient and a maximum leakage current difference value, and determining a leakage current threshold value according to the leakage current difference history coefficient, the environment coefficient and the maximum leakage current difference value.

8. The method according to claim 7, further comprising determining a maximum leakage current and a maximum leakage current difference from the residual sequence.

9. A low-voltage intelligent circuit breaker protection system is characterized by comprising a master type circuit breaker and a plurality of slave type circuit breakers;

the master type circuit breaker is arranged at the low-voltage head end of the power distribution network, and the slave type circuit breaker is arranged at the low-voltage head end, the low-voltage branch or the low-voltage tail end of the power distribution network;

the master type circuit breaker and the slave type circuit breaker are used for acquiring the leakage current value of the power distribution network and the leakage current variation in unit time;

the slave type circuit breaker is also used for uploading the leakage current value of the power distribution network and the leakage current variation in unit time to the master type circuit breaker;

the master type circuit breaker is further used for determining a leakage current threshold value and a current variation threshold value, determining whether the corresponding master type circuit breaker or the slave type circuit breaker needs to be subjected to circuit breaking protection or not according to the leakage current value of the power distribution network, the leakage current variation in unit time, the leakage current threshold value and the current variation threshold value, issuing a circuit breaking protection instruction to the slave type circuit breaker if the slave type circuit breaker needs to be subjected to circuit breaking protection, and performing circuit breaking protection after the slave type circuit breaker receives the instruction.

10. The protection system of a low-voltage intelligent circuit breaker according to claim 9, wherein the master type circuit breaker is further configured to issue a remote control pre-execution command to the slave type circuit breaker, the slave type circuit breaker is further configured to respond to a function code of pre-execution confirmation after receiving the remote control pre-execution command, the master type circuit breaker sends a remote control opening, closing or cancellation command to the slave type circuit breaker after receiving the function code of pre-execution confirmation, and the slave type circuit breaker performs an opening action, a closing action or a cancellation of an executing action according to the remote control opening, closing or cancellation command and responds to the function code of execution confirmation to the master type circuit breaker.

Technical Field

The invention relates to the technical field of leakage protection, in particular to a method and a system for protecting a low-voltage intelligent circuit breaker.

Background

The leakage protector is mainly used for protecting the electric shock of a person with fatal danger when the equipment has leakage faults, has overload and short-circuit protection functions, can be used for protecting the overload and short circuit of a circuit or a motor, and can also be used for the infrequent switching and starting of the circuit under normal conditions. The leakage current of the low-voltage line shows a stable and increasing change process under the influence of factors such as insulation aging of power grid equipment, leakage of electric equipment, running time transition and the like; and the leakage current is less compared with the personal electric shock current, so that the traditional leakage protector cannot realize accurate judgment and correct action, the leakage protector is easy to malfunction, and the power supply reliability is reduced due to frequent false tripping.

Disclosure of Invention

In view of the above, it is desirable to provide a method and a system for protecting a low-voltage intelligent circuit breaker, so as to solve the problem that the conventional leakage protector is prone to malfunction.

The invention provides a protection method of a low-voltage intelligent circuit breaker, which comprises the following steps:

acquiring the leakage current value of the power distribution network and the leakage current variable quantity in unit time;

determining a leakage current threshold value and a current variation threshold value, and issuing the leakage current threshold value and the current variation threshold value;

and determining whether to perform open circuit protection according to the leakage current value of the power distribution network, the leakage current variation in unit time, the leakage current threshold and the current variation threshold.

Further, according to distribution network leakage current value, the amount of leakage current change in unit time, the leakage current threshold and the amount of current change threshold, whether to carry out the protection of opening circuit is determined, specifically including: and if the leakage current value of the power distribution network is greater than the leakage current threshold value and lasts for a set time length, or the leakage current variation in unit time is greater than the current variation threshold value, performing open circuit protection, otherwise, not performing open circuit protection.

Further, the determining the leakage current threshold specifically includes: and measuring the current average value of the electric leakage of the power distribution network, taking the current average value of the electric leakage of the power distribution network as a current reference value, and determining an electric leakage current threshold value according to the current reference value.

Further, determining a leakage current threshold according to the current reference value specifically includes: and subtracting the current reference value from the sequence of the leakage current to obtain a residual sequence, acquiring the standard deviation of the residual sequence, and taking the sum of the reference value and the standard deviation of the multiple residual sequence as the leakage current threshold value.

Further, the determining the leakage current threshold specifically includes obtaining a ratio between the load current and the leakage current at different times, obtaining a moving average value according to the ratio between the load current and the leakage current at different times, obtaining a residual sequence according to the moving average value, a theoretical value of the leakage circuit, and a sequence of the leakage current, obtaining a standard deviation of the residual sequence, and taking a sum of a reference value and a standard deviation of a multiple of the residual sequence as the leakage current threshold.

Further, the determining the leakage current threshold specifically includes: and acquiring a history coefficient, an environment coefficient and a maximum value of the leakage current, and determining a leakage current threshold according to the history coefficient, the environment coefficient and the maximum value of the leakage current.

Further, the determining the current variation threshold specifically includes: the determining of the current variation threshold specifically includes: and obtaining a leakage current difference history coefficient, an environment coefficient and a maximum leakage current difference value, and determining a leakage current threshold value according to the leakage current difference history coefficient, the environment coefficient and the maximum leakage current difference value.

Further, the protection method of the intelligent low-voltage circuit breaker further comprises the step of determining the maximum value of the leakage current and the maximum difference value of the leakage current through the residual sequence.

The invention also provides a low-voltage intelligent circuit breaker protection system, which comprises a master type circuit breaker and a plurality of slave type circuit breakers;

the master type circuit breaker is arranged at the low-voltage head end of the power distribution network, and the slave type circuit breaker is arranged at the low-voltage head end, the low-voltage branch or the low-voltage tail end of the power distribution network;

the master type circuit breaker and the slave type circuit breaker are used for acquiring the leakage current value of the power distribution network and the leakage current variation in unit time;

the slave type circuit breaker is also used for uploading the leakage current value of the power distribution network and the leakage current variation in unit time to the master type circuit breaker;

the master type circuit breaker is further used for determining a leakage current threshold value and a current variation threshold value, determining whether the corresponding master type circuit breaker or the slave type circuit breaker needs to be subjected to circuit breaking protection or not according to the leakage current value of the power distribution network, the leakage current variation in unit time, the leakage current threshold value and the current variation threshold value, issuing a circuit breaking protection instruction to the slave type circuit breaker if the slave type circuit breaker needs to be subjected to circuit breaking protection, and performing circuit breaking protection after the slave type circuit breaker receives the instruction.

The master type circuit breaker is further used for issuing a remote control pre-execution command to the slave type circuit breaker, the slave type circuit breaker is further used for responding to a function code confirmed by pre-execution after receiving the remote control pre-execution command, the master type circuit breaker sends a remote control opening, closing or canceling command to the slave type circuit breaker after receiving the function code confirmed by pre-execution, and the slave type circuit breaker executes opening, closing or canceling command or canceling executing action according to the remote control opening, closing or canceling command and responds to the function code confirmed by executing to the master type circuit breaker.

Compared with the prior art, the invention has the beneficial effects that: the leakage current value of the power distribution network and the leakage current variable quantity in unit time are obtained; determining a leakage current threshold value and a current variation threshold value, and issuing the leakage current threshold value and the current variation threshold value; and determining whether to perform open circuit protection according to the leakage current value of the power distribution network, the leakage current variation in unit time, the leakage current threshold and the current variation threshold. The misoperation of the leakage protector can be effectively prevented.

Drawings

Fig. 1 is a schematic flow chart illustrating a protection method for a low-voltage intelligent circuit breaker according to an embodiment of the present invention.

Detailed Description

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate preferred embodiments of the invention and together with the description, serve to explain the principles of the invention and not to limit the scope of the invention.

The invention provides a protection method of a low-voltage intelligent circuit breaker, wherein the flow schematic diagram of an embodiment is shown in fig. 1, and in the embodiment, the protection method of the low-voltage intelligent circuit breaker comprises the following steps:

s1, acquiring a power distribution network leakage current value and a leakage current variable quantity in unit time;

s2, determining a leakage current threshold and a current variation threshold, and issuing the leakage current threshold and the current variation threshold;

and S3, determining whether to perform open circuit protection according to the leakage current value of the power distribution network, the leakage current variation in unit time, the leakage current threshold and the current variation threshold.

It should be noted that, low pressure wisdom circuit breaker essence is a earth-leakage protector, through above-mentioned technical scheme, can effectively prevent earth-leakage protector's maloperation.

As a preferred embodiment, determining whether to perform the open-circuit protection according to the power distribution network leakage current value, the leakage current variation in unit time, the leakage current threshold, and the current variation threshold specifically includes: and if the leakage current value of the power distribution network is greater than the leakage current threshold value and lasts for a set time length, or the leakage current variation in unit time is greater than the current variation threshold value, performing open circuit protection, otherwise, not performing open circuit protection.

As a preferred embodiment, the determining the leakage current threshold specifically includes: and measuring the current average value of the electric leakage of the power distribution network, taking the current average value of the electric leakage of the power distribution network as a current reference value, and determining an electric leakage current threshold value according to the current reference value.

In one embodiment, the leakage current reference value is obtained using a running average and is calculated by the formula

Wherein, x (k-i) represents the k-i leakage current data, k represents the serial number of the current leakage current data, and the meaning of the leakage current reference value calculation formula is accumulated to x (k-N) from x (k) and then an average value is taken.

As a preferred embodiment, determining the leakage current threshold according to the current reference value specifically includes: and subtracting the current reference value from the sequence of the leakage current to obtain a residual sequence, acquiring the standard deviation of the residual sequence, and taking the sum of the reference value and the standard deviation of the multiple residual sequence as the leakage current threshold value.

It should be noted that the standard deviation of the multiple residual sequence may be two or three times of the standard deviation of the residual sequence, etc.

As a preferred embodiment, the determining the leakage current threshold specifically includes obtaining a ratio between the load current and the leakage current at different times, obtaining a moving average value according to the ratio between the load current and the leakage current at different times, obtaining a residual sequence according to the moving average value, a theoretical value of the leakage circuit, and a sequence of the leakage current, obtaining a standard deviation of the residual sequence, and taking a sum of a reference value and a standard deviation of a multiple of the residual sequence as the leakage current threshold.

As a preferred embodiment, the determining the leakage current threshold specifically includes: and acquiring a history coefficient, an environment coefficient and a maximum value of the leakage current, and determining a leakage current threshold according to the history coefficient, the environment coefficient and the maximum value of the leakage current.

In a specific embodiment, the leakage current history coefficient may be determined by using a support vector machine or the like according to the leakage current history data, and the environmental coefficient may be obtained by determining a formula according to the environmental coefficient, where the formula for determining the environmental coefficient is

And determining a leakage current threshold value according to the historical leakage current coefficient, the environment coefficient and the maximum leakage current value, specifically, multiplying the historical leakage current coefficient, the environment coefficient and the maximum leakage current value to obtain a fixed leakage current threshold value.

As a preferred embodiment, the determining the current variation threshold specifically includes: and obtaining a leakage current difference history coefficient, an environment coefficient and a maximum leakage current difference value, and determining a leakage current threshold value according to the leakage current difference history coefficient, the environment coefficient and the maximum leakage current difference value.

In a specific embodiment, a leakage current difference history coefficient may be determined by using a method such as a support vector machine according to the leakage current difference history data, and a leakage current threshold may be determined according to the leakage current difference history coefficient, an environment coefficient, and a maximum leakage current difference value, specifically, the leakage current threshold is obtained by multiplying the leakage current difference history coefficient, the environment coefficient, and the maximum leakage current difference value.

As a preferred embodiment, the method for protecting a low-voltage intelligent circuit breaker further includes determining a maximum leakage current value and a maximum leakage current difference value through the residual sequence.

In one embodiment, a ratio k (i) between the load current y (i) and the leakage current x (i) is calculated, and a running average of the ratio k (i) is calculatedComputingAnd taking delta (i) as a residual sequence. And determining the maximum value and the maximum difference value of the leakage current through the residual sequence, specifically, determining the maximum value and the maximum difference value of the leakage current by taking the residual sequence as a new leakage current sequence and taking the new leakage current sequence.

The embodiment of the invention provides a low-voltage intelligent circuit breaker protection system, which comprises a master type circuit breaker and a plurality of slave type circuit breakers, wherein the master type circuit breaker is connected with the slave type circuit breakers through a network;

the master type circuit breaker is arranged at the low-voltage head end of the power distribution network, and the slave type circuit breaker is arranged at the low-voltage head end, the low-voltage branch or the low-voltage tail end of the power distribution network;

the master type circuit breaker and the slave type circuit breaker are used for acquiring the leakage current value of the power distribution network and the leakage current variation in unit time;

the slave type circuit breaker is also used for uploading the leakage current value of the power distribution network and the leakage current variation in unit time to the master type circuit breaker;

the master type circuit breaker is further used for determining a leakage current threshold value and a current variation threshold value, determining whether the corresponding master type circuit breaker or the slave type circuit breaker needs to be subjected to circuit breaking protection or not according to the leakage current value of the power distribution network, the leakage current variation in unit time, the leakage current threshold value and the current variation threshold value, issuing a circuit breaking protection instruction to the slave type circuit breaker if the slave type circuit breaker needs to be subjected to circuit breaking protection, and performing circuit breaking protection after the slave type circuit breaker receives the instruction.

As a preferred embodiment, the master type circuit breaker is further configured to issue a remote control pre-execution command to a slave type circuit breaker, the slave type circuit breaker is further configured to respond to a function code confirmed by pre-execution after receiving the remote control pre-execution command, the master type circuit breaker sends a remote control opening, closing or canceling command to the slave type circuit breaker after receiving the function code confirmed by pre-execution, and the slave type circuit breaker executes an opening action, a closing action or canceling an executing action according to the remote control opening, closing or canceling command and responds to the function code confirmed by the master type circuit breaker.

In a specific embodiment, the master circuit breaker is further configured to issue a remote control pre-execution command to the slave circuit breaker, the slave circuit breaker resolves that a frame type of a protocol frame issued by the master circuit breaker is the remote control pre-execution command, and the slave circuit breaker responds to a function code confirmed by pre-execution; after receiving the protocol frame of pre-execution confirmation responded by the slave circuit breaker, the master circuit breaker sends a remote control execution (switching-off or switching-on) or cancellation command, and the slave circuit breaker responds to a function code response of confirmation execution; and if the switching-off or switching-on execution command is sent by the master machine, the slave machine executes the corresponding switching-off or switching-on action.

The invention provides a low-voltage intelligent circuit breaker protection method and system, which are characterized in that a leakage current value of a power distribution network and a leakage current variable quantity in unit time are obtained; determining a leakage current threshold value and a current variation threshold value, and issuing the leakage current threshold value and the current variation threshold value; and determining whether to perform open circuit protection according to the leakage current value of the power distribution network, the leakage current variation in unit time, the leakage current threshold and the current variation threshold. The misoperation of the leakage protector can be effectively prevented, and the power supply reliability is improved.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.