Over-current protection test method based on simulation of protection characteristics of thermomagnetic release

Abstract

The invention relates to the technical field of ship power systems, in particular to a power system overcurrent protection test method based on simulation of protection characteristics of a thermomagnetic release. According to the invention, the overload and short-circuit protection test of the power system is carried out by simulating the overcurrent protection characteristic of the thermomagnetic release through the electronic release, so that the selectivity and effectiveness of the overcurrent protection design of the power system can be verified, and the defect that the overcurrent simulation test cannot be carried out by the thermomagnetic release in the prior art is overcome; and the conditions of electric arc, ablation and the like caused by high-current breaking of the circuit breaker are avoided. The over-current protection simulation test method is provided for the power system provided with the thermomagnetic release, and the correctness of system protection design can be accurately and efficiently verified.

Description

Technical Field

[0001] The invention relates to the technical field of ship power systems, and in particular to a power system overcurrent protection test method based on simulating the protection characteristics of a thermal magnetic release. Background Art

[0002] Overcurrent faults in power systems are common system faults. Improper system protection design may lead to power outages on the entire ship or even more serious consequences. Therefore, before the power system is installed on a ship, the selectivity and effectiveness of the system protection design are generally verified through power system protection tests. However, conducting large current protection tests on power systems requires a lot of test funds. At the same time, the circuit breaker will cause ablation to the body when breaking the large test current. The larger the installed capacity of the system, the greater the test funds required and the harm caused by the test. Therefore, a simulation test method that does not require actual current flow can be sought.

[0003] The power system usually uses frame circuit breakers as protection devices for the power supply network, and uses thermal-magnetic molded case circuit breakers and electronic molded case circuit breakers as protection devices for the distribution network. Currently, both frame circuit breakers and electronic molded case circuit breakers are equipped with electronic releases, and thermal-magnetic molded case circuit breakers are equipped with thermal-magnetic releases. The main difference between the electronic release and the thermal-magnetic release in the tripping action link is that the former is that the electronic release outputs a tripping signal to the magnetic flux converter to drive the opening mechanism to act, while the latter directly acts on the opening mechanism, and the opening mechanism will produce arcs, ablation and other hazards at the moment of action. In view of the above differences, there is no need for the opening mechanism to act. It is only necessary to check whether the magnetic flux converter in the electronic release is in action to determine whether the release is in action, that is, the electronic release can use a simulation method to determine whether the release is in action without actual disconnection. The tripping process of the thermal-magnetic release lacks an intermediate link, so it is impossible to use a simulation test method. At the same time, given that the electronic release can flexibly adjust the protection parameters within a certain range, it has the conditions to "imitate" the thermal-magnetic release.

[0004] In view of the above situation, the present invention proposes a power system overcurrent protection test method based on simulating the protection characteristics of a thermal-magnetic release. Summary of the invention

[0005] The technical problem to be solved by the present invention is: to provide a power system overcurrent protection test method based on simulating the protection characteristics of a thermal-magnetic release, which can carry out power system overload protection tests by simulating the long delay and instantaneous protection characteristics of a thermal-magnetic release through an electronic release, and verify the selectivity and effectiveness of the power system overcurrent protection design.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] An overcurrent protection test method based on simulating the protection characteristics of a thermal magnetic release mainly includes the following steps:

[0008] S1, select the electronic release for testing with the corresponding rated current according to the structure of the initial power supply and distribution branch to be tested in the power system;

[0009] S2, setting the protection parameters of the test electronic release based on the protection parameters of the thermal-magnetic release of the lower-level molded case circuit breaker in the initial power supply and distribution branch to be tested;

[0010] S3, replacing the thermal-magnetic release of the lower-level molded case circuit breaker in the initial power supply and distribution branch to be tested with the test electronic release, and then reconnecting it in series to the power supply and distribution branch to be tested to form a replaced power supply and distribution branch to be tested;

[0011] S4, select a suitable current generator or power supply device to generate the test current;

[0012] S5, carrying out an overload test and a short-circuit test on the replaced power supply and distribution branch to be tested.

[0013] Furthermore, the initial power supply and distribution branch to be tested includes a three-level frame circuit breaker and a two-level molded case circuit breaker, and the frame circuit breakers all use electronic releases. The upper molded case circuit breaker in the two-level molded case circuit breaker uses an electronic release, and the lower molded case circuit breaker uses a thermal-magnetic release.

[0014] Furthermore, in the replaced power supply and distribution branch to be tested, the lower-level molded case circuit breaker adopts the test electronic release, and the protection parameters of the test electronic release are set to be consistent with those of the thermal-magnetic release.

[0015] Furthermore, the protection parameters include long-delay protection parameters and instantaneous protection parameters.

[0016] Furthermore, whether the electronic release for testing is actuated is determined by collecting information on whether the electronic release for testing outputs a tripping signal.

[0017] Furthermore, when the electronic release for testing is actuated, its magnetic flux converter is actuated, the output current during the actuation is read by the electronic release for testing, and a corresponding tripping signal is output.

[0018] Furthermore, the overload action time of the overload test is manually recorded by a stopwatch.

[0019] Furthermore, the test current is generated by a current generator, or by a power supply device of a test platform according to test conditions.

[0020] Compared with the prior art, the present invention has the following main advantages:

[0021] 1. The present invention conducts overload and short-circuit protection tests on power systems by simulating the overcurrent protection characteristics of thermal-magnetic releases through electronic releases, which can verify the selectivity and effectiveness of the overcurrent protection design of the power system, making up for the deficiency that thermal-magnetic releases in the prior art cannot conduct overcurrent simulation tests, and avoiding arcs, ablation, etc. caused by large current interruption of the circuit breaker.

[0022] 2. The present invention provides an overcurrent protection simulation test method for a power system equipped with a thermal-magnetic release, which can accurately and efficiently verify the correctness of the system protection design. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of typical power supply and distribution branch circuit breakers connected in series in an embodiment of the present invention;

[0024] Figure 2 It is a schematic diagram of a power system protection simulation test based on simulating the protection characteristics of a thermal-magnetic release in an embodiment of the present invention;

[0025] Figure 3 It is a protection curve comparison diagram of the electronic release 100E of the molded case circuit breaker simulating the characteristics of the thermal magnetic release 100P in the embodiment of the present invention;

[0026] Figure 4 It is a protection curve comparison diagram of the electronic release 200E of the molded case circuit breaker simulating the characteristics of the thermal magnetic release 200P in the embodiment of the present invention;

[0027] Figure 5 The five-level power supply and distribution branch selective protection curve of the embodiment of the present invention with a 200A thermal-magnetic molded case circuit breaker at the end;

[0028] Figure 6 This is a selective protection curve for a five-level power supply and distribution branch circuit with a 100A thermal-magnetic molded case circuit breaker at the end in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0031] Embodiment 1: This embodiment provides an overcurrent protection test method based on simulating the protection characteristics of a thermal magnetic release, which mainly includes the following steps:

[0032] S1, select the electronic release for testing with the corresponding rated current according to the structure of the initial power supply and distribution branch to be tested in the power system;

[0033] S2, setting the protection parameters of the test electronic release based on the protection parameters of the thermal-magnetic release of the lower-level molded case circuit breaker in the initial power supply and distribution branch to be tested;

[0034] S3, replacing the thermal-magnetic release of the lower-level molded case circuit breaker in the initial power supply and distribution branch to be tested with the test electronic release, and then reconnecting it in series to the power supply and distribution branch to be tested to form a replaced power supply and distribution branch to be tested;

[0035] S4, select a suitable current generator or power supply device to generate the test current;

[0036] S5, carrying out an overload test and a short-circuit test on the replaced power supply and distribution branch to be tested.

[0037] Furthermore, the initial power supply and distribution branch to be tested includes a three-level frame circuit breaker and a two-level molded case circuit breaker, and the frame circuit breakers all use electronic releases. The upper molded case circuit breaker in the two-level molded case circuit breaker uses an electronic release, and the lower molded case circuit breaker uses a thermal-magnetic release.

[0038] Furthermore, in the replaced power supply and distribution branch to be tested, the lower-level molded case circuit breaker adopts the test electronic release, and the protection parameters of the test electronic release are set to be consistent with those of the thermal-magnetic release.

[0039] Furthermore, the protection parameters include long-delay protection parameters and instantaneous protection parameters.

[0040] Furthermore, whether the electronic release for testing is actuated is determined by collecting information on whether the electronic release for testing outputs a tripping signal.

[0041] Furthermore, when the electronic release for testing is actuated, its magnetic flux converter is actuated, the output current during the actuation is read by the electronic release for testing, and a corresponding tripping signal is output.

[0042] Furthermore, the overload action time of the overload test is manually recorded by a stopwatch.

[0043] Furthermore, the test current is generated by a current generator, or by a power supply device of a test platform according to test conditions.

[0044] Embodiment 2: This embodiment provides an overcurrent protection test method based on simulating the protection characteristics of a thermal-magnetic release. This method simulates the long-delay and instantaneous protection characteristics of a thermal-magnetic release by using an electronic release to carry out an overload protection test on the power system, thereby verifying the selectivity and effectiveness of the overcurrent protection design of the power system.

[0045] Furthermore, for typical power supply and distribution branches containing thermal-magnetic circuit breakers, a simulation method is used to replace the overload protection test method of directly connecting a large current to the circuit breaker. The series branch containing the thermal-magnetic circuit breaker is replaced with an electronic release series branch, and this method is used to carry out the overcurrent protection test of the power system.

[0046] Furthermore, by utilizing the feature that the protection characteristics of the electronic release can be edited within a certain range, the long-delay protection parameters and instantaneous protection parameters of the electronic release are set with reference to those of the thermal-magnetic release.

[0047] Furthermore, whether the electronic release outputs a trip signal is collected to determine whether the release is actuated.

[0048] Furthermore, the test current may be generated by a current generator, or by a power supply device of a test platform according to test conditions.

[0049] In this embodiment, the typical power supply and distribution branch of the ship power system often includes three-level to four-level frame circuit breakers and three-level or above molded case circuit breakers. The selectivity between frame circuit breakers and between frame circuit breakers and molded case circuit breakers can be well achieved at present. At present, at most two levels of selectivity can be achieved between molded case circuit breakers. Therefore, the typical branch of the power system protection test usually includes a three-level frame circuit breaker and a two-level molded case circuit breaker, such as Figure 1 As shown, the upper molded case circuit breaker usually uses an electronic release, and the lower molded case circuit breaker uses a thermal magnetic release. At the same time, the selectivity between the 100A and 200A molded case circuit breakers and the upper circuit breakers is the focus and difficulty of the protection verification test, so the end circuit breakers of the typical test branch usually select the above two specifications.

[0050] The power system overcurrent protection test method based on simulating the protection characteristics of the thermal magnetic release of the present invention is adopted, and the test process includes the following steps:

[0051] Step 1: Use a 100A or 200A electronic release to set the protection parameters with reference to the thermal magnetic release of the same specification;

[0052] Step 2: Follow Figure 1 The series connection method shown in the figure connects the electronic release devices in series. Figure 2 As shown;

[0053] Step 3: Select a suitable current generator or power supply device to generate the test current;

[0054] Step 4: Reference Figure 2 Complete the installation and wiring of the current generator or test power supply and electronic release, and carry out overload test and short-circuit test respectively. When the protection is activated, the flux converter of the electronic release is activated, and the output current during the action is read by the test electronic release. The overload action time is manually recorded using a stopwatch.

[0055] like Figure 2 As shown in the figure, the last level electronic release of the test branch can be 100A or 200A. According to the above method, the electronic release of the molded case circuit breaker 100E / 200E series is used to simulate the action characteristics of the 100P / 200P series. Figure 3 , Figure 4 In the figure, the curve on the left is the simulation curve of the electronic release, and the curve on the right is the curve of the thermal-magnetic release. The electronic release of the same specification can simulate the thermal-magnetic release well in the long delay range. Due to the structural characteristics of the two types of releases, there is a slight difference in the curves in the instantaneous range.

[0056] Figure 5 and Figure 6 The selective protection curve between 100A or 200A molded case circuit breaker and the upper circuit breaker is shown. Figure 5 and Figure 6 The leftmost side shows the protection curves of 200A and 100A thermal magnetic molded case circuit breakers. Figure 3 , Figure 4 The simulation curve of the electronic release shown is slightly different from that of the thermal-magnetic release, but as the end circuit breaker, it can be seen from the simulation curve that its action is faster and does not affect the effectiveness of the selective protection verification test.

[0057] Furthermore, all parts involved in this application that are not described in detail are the same as the prior art or are implemented using the prior art.

[0058] In summary:

[0059] 1. The present invention conducts overload and short-circuit protection tests on power systems by simulating the overcurrent protection characteristics of thermal-magnetic releases through electronic releases, which can verify the selectivity and effectiveness of the overcurrent protection design of the power system, making up for the deficiency that thermal-magnetic releases in the prior art cannot conduct overcurrent simulation tests, and avoiding arcs, ablation, etc. caused by large current interruption of the circuit breaker.

[0060] 2. The present invention provides an overcurrent protection simulation test method for a power system equipped with a thermal-magnetic release, which can accurately and efficiently verify the correctness of the system protection design.

[0061] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An overcurrent protection test method based on simulating the protection characteristics of a thermal magnetic release, characterized in that: The steps include: S1, select the electronic release for testing with the corresponding rated current according to the structure of the initial power supply and distribution branch to be tested in the power system; S2, setting the protection parameters of the test electronic release based on the protection parameters of the thermal-magnetic release of the lower-level molded case circuit breaker in the initial power supply and distribution branch to be tested; S3, replacing the thermal-magnetic release of the lower-level molded case circuit breaker in the initial power supply and distribution branch to be tested with the test electronic release, and then reconnecting it in series to the power supply and distribution branch to be tested to form a replaced power supply and distribution branch to be tested; S4, select a suitable current generator or power supply device to generate the test current; S5, carrying out an overload test and a short-circuit test on the replaced power supply and distribution branch to be tested.

2. The overcurrent protection test method based on simulating the protection characteristics of the thermal magnetic release according to claim 1 is characterized in that: The initial power supply and distribution branch to be tested includes a three-stage frame circuit breaker and a two-stage molded case circuit breaker. The frame circuit breakers all use electronic releases. The upper molded case circuit breaker in the two-stage molded case circuit breaker uses an electronic release, and the lower molded case circuit breaker uses a thermal magnetic release.

3. The overcurrent protection test method based on simulating the protection characteristics of the thermal magnetic release according to claim 2 is characterized in that: In the replaced power supply and distribution branch to be tested, the lower-level molded case circuit breaker adopts the test electronic release, and the protection parameters of the test electronic release are set to be consistent with those of the thermal-magnetic release.

4. The overcurrent protection test method based on simulating the protection characteristics of a thermal magnetic release according to claim 3 is characterized in that In the protection parameter, the protection parameters include long-delay protection parameters and instantaneous protection parameters.

5. The overcurrent protection test method based on simulating the protection characteristics of a thermal magnetic release according to claim 1 is characterized in that In the method, whether the electronic release for testing is actuated is determined by collecting whether the electronic release for testing outputs a tripping signal.

6. The overcurrent protection test method based on simulating the protection characteristics of a thermal magnetic release according to claim 7, characterized in that: When the electronic release for testing is actuated, its magnetic flux converter is actuated, the output current during the actuation is read by the electronic release for testing, and a corresponding tripping signal is outputted.

7. An overcurrent protection test method based on simulating the protection characteristics of a thermal-magnetic release according to claim 1, characterized in that the overload action time of the overload test is manually recorded by a stopwatch.

8. The overcurrent protection test method based on simulating the protection characteristics of a thermal magnetic release according to claim 1, characterized in that: The test current is generated by a current generator, or by a power supply device of a test platform according to test conditions.

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