A nuclear reactor coolant pump motor primary flow system and method

Abstract

The present invention belongs to the technical field of power commissioning and power testing, and specifically relates to a primary flow system and method for a nuclear reactor coolant pump motor. The present invention comprises a speed I medium-voltage switch cabinet, a speed I cable, an electrical penetration, a speed II medium-voltage switch cabinet, a speed II cable, an electrical penetration, and a nuclear reactor coolant pump motor. The speed I medium-voltage switch cabinet is connected to the nuclear reactor coolant pump motor via the speed I cable and the electrical penetration, and the speed II medium-voltage switch cabinet is connected to the nuclear reactor coolant pump motor via the speed II cable and the electrical penetration. The present invention can detect and find out the problem of wire breakage in the winding, electrical penetration and cable wiring of the nuclear reactor coolant pump motor, check the correctness of the secondary circuit wiring of the motor differential protection CT, ensure the accuracy and reliability of the primary flow test results, and provide reliable guarantee for the safe commissioning of the nuclear reactor coolant pump motor.

Description

Technical Field

[0001] The invention belongs to the technical field of electric power commissioning and electric power testing, and in particular relates to a primary flow system and method for a nuclear reactor coolant pump motor. Background Art

[0002] The reactor coolant pump motor of a pressurized water reactor nuclear power plant is used to drive the reactor coolant pump installed in the primary loop of the reactor. Asynchronous motors are generally used for nuclear reactor coolant pump motors, and their power is generally above 2000kW. Differential protection is configured according to the regulations. The nuclear reactor coolant pump motor is arranged in the nuclear island containment building, and its electrical wiring is led out to the power switch and protection equipment of the conventional island building through the electrical penetration of the containment building. There are many intermediate transfer ports for the electrical wiring of the nuclear reactor coolant pump motor, and circuit disconnection and wiring errors are prone to occur during installation and maintenance. During the commissioning and maintenance test of the nuclear power unit, the nuclear reactor coolant pump motor should be tested for a primary current flow test to check the installation quality of the motor winding, electrical penetration and cable wiring, and verify the correctness of the secondary circuit wiring of the differential protection CT to ensure that the nuclear reactor coolant pump motor is safely put into operation. In the existing nuclear reactor coolant pump motor using a dual-speed asynchronous motor, during a primary current test, an AC current is usually passed between the two phases on the feeder cable side of the I speed main power switch to perform a primary current flow of the I speed differential protection, and an AC current is passed between the two phases on the feeder cable side of the II speed main power switch to perform a primary current flow of the II speed differential protection. The CT constituting the I speed differential protection and the other CT constituting the II speed differential protection in the motor body will flow with currents of the same amplitude and phase, which are difficult to distinguish and judge, resulting in inaccurate test results. Summary of the invention

[0003] The purpose of the present invention is to address the deficiencies in the primary flow of the existing nuclear reactor coolant pump double-speed asynchronous motor, and to provide a nuclear reactor coolant pump motor primary flow system and method, which can detect and discover the problems of wire breakage in the nuclear reactor coolant pump motor windings, electrical penetrations and cable wiring, and verify the correctness of the secondary circuit wiring of the motor differential protection CT, so as to ensure that the primary flow test results are accurate and reliable, and provide reliable protection for the safe commissioning of the nuclear reactor coolant pump motor.

[0004] The technical solution adopted by the present invention is:

[0005] A primary flow system for a nuclear reactor coolant pump motor comprises a speed I medium-voltage switch cabinet, a speed I cable, an electrical penetration, a speed II medium-voltage switch cabinet, a speed II cable, an electrical penetration, and a nuclear reactor coolant pump motor. The speed I medium-voltage switch cabinet is connected to the nuclear reactor coolant pump motor via the speed I cable and the electrical penetration, and the speed II medium-voltage switch cabinet is connected to the nuclear reactor coolant pump motor via the speed II cable and the electrical penetration.

[0006] It also includes a speed differential protection relay I. The current transformer TA7 of the speed I medium-voltage switchgear 1 and the current transformer TA5 of the nuclear reactor coolant pump motor are connected to the speed differential protection relay I to form a speed A-phase differential protection; the current transformer TA8 of the speed I medium-voltage switchgear and the current transformer TA6 of the nuclear reactor coolant pump motor are connected to the speed differential protection relay I to form a speed B-phase differential protection; the current transformer TA9 of the speed I medium-voltage switchgear and the current transformer TA4 of the nuclear reactor coolant pump motor are connected to the speed differential protection relay I to form a speed C-phase differential protection.

[0007] It also includes a II speed differential protection relay. The current transformer TA10 of the II speed medium-voltage switchgear and the current transformer TA1 of the nuclear reactor coolant pump motor are connected to the II speed differential protection relay to form II speed A phase differential protection; the current transformer TA11 of the II speed medium-voltage switchgear and the current transformer TA2 of the nuclear reactor coolant pump motor are connected to the II speed differential protection relay to form II speed B phase differential protection; the current transformer TA12 of the II speed medium-voltage switchgear and the current transformer TA3 of the nuclear reactor coolant pump motor are connected to the II speed differential protection relay to form II speed C phase differential protection.

[0008] It also includes a single-phase voltage regulator, the output terminals of the single-phase voltage regulator are respectively connected to the cable side static contact point A1 of the I speed medium-voltage switch cabinet and the cable connection copper busbar point B20 of the II speed medium-voltage switch cabinet when the I speed A phase differential protection is turned on for the first time; the output terminals of the single-phase voltage regulator are respectively connected to the cable side static contact point B1 of the I speed medium-voltage switch cabinet and the cable connection copper busbar point C20 of the II speed medium-voltage switch cabinet when the I speed B phase differential protection is turned on for the first time; the output terminals of the single-phase voltage regulator are respectively connected to the cable side static contact point C1 of the I speed medium-voltage switch cabinet and the cable connection copper busbar point A20 of the II speed medium-voltage switch cabinet when the I speed C phase differential protection is turned on for the first time.

[0009] The output terminals of the single-phase voltage regulator are respectively connected to the static contact point A2 on the cable side of the Ⅱ speed medium-voltage switchgear and the cable connection copper busbar point A10 of the Ⅱ speed medium-voltage switchgear when the Ⅱ speed A phase differential protection is turned on once; the output terminals of the single-phase voltage regulator are respectively connected to the static contact point B2 on the cable side of the Ⅱ speed medium-voltage switchgear and the cable connection copper busbar point B10 of the Ⅱ speed medium-voltage switchgear when the Ⅱ speed B phase differential protection is turned on once; the output terminals of the single-phase voltage regulator are respectively connected to the static contact point C2 on the cable side of the Ⅱ speed medium-voltage switchgear and the cable connection copper busbar point C10 of the Ⅱ speed medium-voltage switchgear when the Ⅱ speed C phase differential protection is turned on once.

[0010] A flow-through method for a primary flow-through system of a nuclear reactor coolant pump motor comprises the following steps:

[0011] Step 1 is to prepare for a flow test of a nuclear reactor coolant pump motor, and after all the preliminary preparations are completed, proceed to step 2;

[0012] Step 2: Perform the primary current flow of the A-phase differential protection of the I speed: connect the output terminal of the single-phase voltage regulator to the static contact point A1 of the cable side of the I speed medium-voltage switch cabinet and the cable connection copper bar B20 of the II speed medium-voltage switch cabinet, then turn on the power of the single-phase voltage regulator to pass a 20A primary current, measure and record the secondary current of each CT, turn off the power of the single-phase voltage regulator and proceed to step 3;

[0013] Step 3: Perform the primary current flow of the B-phase differential protection of the I speed: connect the output terminal of the single-phase voltage regulator to the cable side static contact B1 point of the I speed medium-voltage switch cabinet and the cable connection copper bar C20 point of the II speed medium-voltage switch cabinet respectively, then turn on the power supply of the single-phase voltage regulator to pass a 20A primary current, measure and record the secondary current of each CT, turn off the power supply of the single-phase voltage regulator and proceed to step 4;

[0014] Step 4: Perform the primary current flow of the C-phase differential protection of the I speed: connect the output terminal of the single-phase voltage regulator to the static contact C1 point of the cable side of the I speed medium-voltage switch cabinet and the cable connection copper bar A20 point of the II speed medium-voltage switch cabinet, then turn on the power supply of the single-phase voltage regulator to pass a 20A primary current, measure and record the secondary current of each CT, turn off the power supply of the single-phase voltage regulator and proceed to step 5;

[0015] Step 5: Perform the primary current flow of the A-phase differential protection of the II speed: connect the output terminal of the single-phase voltage regulator to the static contact point A2 of the cable side of the II speed medium-voltage switch cabinet and the cable connection copper bar A10 of the II speed medium-voltage switch cabinet, then turn on the power of the single-phase voltage regulator to pass a 20A primary current, measure and record the secondary current of each CT, turn off the power of the single-phase voltage regulator and proceed to step 6;

[0016] Step 6: Perform the primary current flow of the B-phase differential protection of the II speed: connect the output terminal of the single-phase voltage regulator 10 to the static contact B2 point of the cable side of the II speed medium-voltage switch cabinet and the cable connection copper bar B10 point of the II speed medium-voltage switch cabinet respectively, then turn on the power of the single-phase voltage regulator to pass a 20A primary current, measure and record the secondary current of each CT, turn off the power of the single-phase voltage regulator and proceed to step 7;

[0017] Step 7: Perform the primary current flow of the C-phase differential protection of the speed II: connect the output terminal of the single-phase voltage regulator to the static contact C2 point of the cable side of the speed II medium-voltage switch cabinet and the cable connection copper bar C10 point of the speed II medium-voltage switch cabinet, then turn on the power of the single-phase voltage regulator to pass a 20A primary current, measure and record the secondary current of each CT, turn off the power of the single-phase voltage regulator and proceed to step 8;

[0018] Step 8 determines whether the secondary current of each CT is consistent with the theoretical value. If the amplitude deviation of the secondary current of each CT and the theoretical value is within ±5% and the phase deviation is within ±2°, proceed to step 10; otherwise, proceed to step 9.

[0019] Step 9: Confirm that the power supply of the single-phase voltage regulator is turned off, find and eliminate the defects, and then proceed to step 2;

[0020] Step 10: The first flow test of the nuclear reactor coolant pump motor is completed.

[0021] The specific process of step 1 is as follows:

[0022] Step 101 checks and confirms that the main power switch Q1 of the I speed medium voltage switch cabinet has been disconnected and withdrawn for isolation, and checks and confirms that the main power switch Q2 of the II speed medium voltage switch cabinet has been disconnected and withdrawn for isolation;

[0023] Step 102: Check and confirm that the electrical wiring of the primary flow system of the nuclear reactor coolant pump motor is fully connected, and check and confirm that all CT terminal strips are firmly connected;

[0024] Step 103: Check and confirm that the grounding switch QE1 of the medium-voltage switch cabinet of speed I is disconnected, and check and confirm that the grounding switch QE2 of the medium-voltage switch cabinet of speed II is disconnected;

[0025] Step 104 checks and confirms that the insulation resistance of the primary flow system of the nuclear reactor coolant pump motor meets the requirements.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The present invention provides a primary flow system for a nuclear reactor coolant pump motor. For a nuclear reactor coolant pump motor using a dual-speed asynchronous motor, the electrical wiring of the nuclear reactor coolant pump motor does not need to be changed during the test. Only the main power switch and the grounding switch of the medium-voltage switch cabinet need to be isolated, and the test conditions are simple.

[0028] (2) The present invention provides a primary current passing method for a nuclear reactor coolant pump motor, wherein a primary current is passed between a static contact on the cable side of one of the main power switches of the nuclear reactor coolant pump motor and a cable connection copper busbar of another main power switch, so that the secondary currents of each group of CTs can be easily distinguished and identified, and the disconnection problem of the electrical circuit of the nuclear reactor coolant pump motor can be discovered, and the correctness of the secondary circuit wiring of the differential protection CT of the nuclear reactor coolant pump motor can be accurately checked. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the principle of the primary flow system of the nuclear reactor coolant pump motor of the present invention;

[0030] Figure 2 The present invention is a flow chart of a primary flow test of a nuclear reactor coolant pump motor.

[0031] In the figure: 1 is a speed I medium-voltage switch cabinet, 2 is a speed I cable, 3 is an electrical penetration, 4 is a speed I differential protection relay, 5 is a speed II medium-voltage switch cabinet, 6 is a speed II cable, 7 is an electrical penetration, 8 is a speed II differential protection relay, 9 is a nuclear reactor coolant pump motor, 10 is a single-phase voltage regulator, 10-1 is a single-phase voltage regulator output terminal, and 10-2 is a single-phase voltage regulator output terminal. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0034] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] The primary flow system of the nuclear reactor coolant pump motor described in the present invention comprises a I speed medium voltage switch cabinet 1, an I speed cable 2, an electrical penetration 3, an I speed differential protection relay 4, a II speed medium voltage switch cabinet 5, a II speed cable 6, an electrical penetration 7, a II speed differential protection relay 8, a nuclear reactor coolant pump motor 9 and a single-phase voltage regulator 10.

[0036] The I speed medium voltage switch cabinet 1 is connected to the nuclear reactor coolant pump motor 9 via the I speed cable 2 and the electrical penetration 3, and the II speed medium voltage switch cabinet 5 is connected to the nuclear reactor coolant pump motor 9 via the II speed cable 6 and the electrical penetration 7.

[0037] The current transformer TA7 of the I speed medium voltage switch cabinet 1 and the current transformer TA5 of the nuclear reactor coolant pump motor 9 are connected to the I speed differential protection relay 4 to form the I speed A phase differential protection; the current transformer TA8 of the I speed medium voltage switch cabinet 1 and the current transformer TA6 of the nuclear reactor coolant pump motor 9 are connected to the I speed differential protection relay 4 to form the I speed B phase differential protection; the current transformer TA9 of the I speed medium voltage switch cabinet 1 and the current transformer TA4 of the nuclear reactor coolant pump motor 9 are connected to the I speed differential protection relay 4 to form the I speed C phase differential protection; The current transformer TA10 of the II speed medium-voltage switchgear 5 and the current transformer TA1 of the nuclear reactor coolant pump motor 9 are connected to the II speed differential protection relay 8 to constitute the II speed A phase differential protection; the current transformer TA11 of the II speed medium-voltage switchgear 5 and the current transformer TA2 of the nuclear reactor coolant pump motor 9 are connected to the II speed differential protection relay 8 to constitute the II speed B phase differential protection; the current transformer TA12 of the II speed medium-voltage switchgear 5 and the current transformer TA3 of the nuclear reactor coolant pump motor 9 are connected to the II speed differential protection relay 7 to constitute the II speed C phase differential protection.

[0038] The output terminals 10-1 and 10-2 of the single-phase voltage regulator are respectively connected to the static contact point A1 of the cable side of the medium-voltage switch cabinet 1 of the speed I and the cable connection copper bar B20 of the medium-voltage switch cabinet 5 of the speed II when the differential protection of the phase A of the speed I is turned on once; the output terminals 10-1 and 10-2 of the single-phase voltage regulator are respectively connected to the static contact point B1 of the cable side of the medium-voltage switch cabinet 1 of the speed I and the cable connection copper bar C20 of the medium-voltage switch cabinet 5 of the speed II when the differential protection of the phase B of the speed I is turned on once; the output terminals 10-1 and 10-2 of the single-phase voltage regulator are respectively connected to the static contact point C1 of the cable side of the medium-voltage switch cabinet 1 of the speed I and the cable connection copper bar A20 of the medium-voltage switch cabinet 5 of the speed II when the differential protection of the phase C of the speed I is turned on once; The output terminals 10-1 and 10-2 of the single-phase voltage regulator are respectively connected to the static contact point A2 on the cable side of the Ⅱ speed medium-voltage switch cabinet 5 and the cable connection copper busbar point A10 of the Ⅱ speed medium-voltage switch cabinet 1 when the Ⅱ speed A phase differential protection is turned on once; the output terminals 10-1 and 10-2 of the single-phase voltage regulator are respectively connected to the static contact point B2 on the cable side of the Ⅱ speed medium-voltage switch cabinet 5 and the cable connection copper busbar point B10 of the Ⅱ speed medium-voltage switch cabinet 1 when the Ⅱ speed B phase differential protection is turned on once; the output terminals 10-1 and 10-2 of the single-phase voltage regulator are respectively connected to the static contact point C2 on the cable side of the Ⅱ speed medium-voltage switch cabinet 5 and the cable connection copper busbar point C10 of the Ⅱ speed medium-voltage switch cabinet 1 when the Ⅱ speed C phase differential protection is turned on once.

[0039] The present invention discloses a method for passing a flow through a nuclear reactor coolant pump motor. The method is applicable to the following objects: Figure 2 A nuclear reactor coolant pump motor primary flow system is shown.

[0040] like Figure 1 and Figure 2 As shown, a method for passing a nuclear reactor coolant pump motor once according to the present invention comprises the following steps:

[0041] 1) Carry out the preparation work for the primary flow test of the nuclear reactor coolant pump motor, and proceed to step 2) after all the preliminary preparation work is completed;

[0042] 2) Perform the primary current flow of the A-phase differential protection of the I speed: connect the output terminals 10-1 and 10-2 of the single-phase voltage regulator to the static contact point A1 of the cable side of the I speed medium-voltage switch cabinet 1 and the cable connection copper bar B20 of the II speed medium-voltage switch cabinet 5, respectively, then turn on the power supply of the single-phase voltage regulator 10 to pass a 20A primary current, measure and record the secondary current of each CT, turn off the power supply of the single-phase voltage regulator 10 and proceed to step 3);

[0043] 3) Carry out the primary current flow of the B-phase differential protection of the I speed: connect the output terminals 10-1 and 10-2 of the single-phase voltage regulator to the cable side static contact point B1 of the I speed medium-voltage switch cabinet 1 and the cable connection copper bar C20 of the II speed medium-voltage switch cabinet 5 respectively, then turn on the power supply of the single-phase voltage regulator 10 to pass a 20A primary current, measure and record the secondary current of each CT, turn off the power supply of the single-phase voltage regulator 10 and proceed to step 4);

[0044] 4) Perform the primary current flow of the C-phase differential protection at speed I: connect the output terminals 10-1 and 10-2 of the single-phase voltage regulator to the static contact C1 point of the cable side of the medium-voltage switch cabinet 1 at speed I and the cable connection copper bar A20 point of the medium-voltage switch cabinet 5 at speed II respectively, then turn on the power supply of the single-phase voltage regulator 10 to pass a primary current of 20A, measure and record the secondary current of each CT, turn off the power supply of the single-phase voltage regulator 10 and proceed to step 5);

[0045] 5) Perform the primary current flow of the A-phase differential protection of the speed II: connect the output terminals 10-1 and 10-2 of the single-phase voltage regulator to the static contact point A2 of the cable side of the speed II medium-voltage switch cabinet 5 and the cable connection copper bar A10 of the speed II medium-voltage switch cabinet 1, respectively, then turn on the power supply of the single-phase voltage regulator 10 to pass a 20A primary current, measure and record the secondary current of each CT, turn off the power supply of the single-phase voltage regulator 10 and proceed to step 6);

[0046] 6) Perform the primary current flow of the II speed B phase differential protection: connect the output terminals 10-1 and 10-2 of the single-phase voltage regulator to the cable side static contact point B2 of the II speed medium voltage switch cabinet 5 and the cable connection copper bar B10 of the II speed medium voltage switch cabinet 1 respectively, then turn on the power supply of the single-phase voltage regulator 10 to pass a 20A primary current, measure and record the secondary current of each CT, turn off the power supply of the single-phase voltage regulator 10 and proceed to step 7);

[0047] 7) Perform the primary current flow of the II speed C phase differential protection: connect the output terminals 10-1 and 10-2 of the single-phase voltage regulator to the static contact C2 point of the cable side of the II speed medium voltage switch cabinet 5 and the cable connection copper bar C10 point of the II speed medium voltage switch cabinet 1 respectively, then turn on the power supply of the single-phase voltage regulator 10 to pass a 20A primary current, measure and record the secondary current of each CT, turn off the power supply of the single-phase voltage regulator 10 and proceed to step 8);

[0048] 8) Determine whether the secondary current of each CT is consistent with the theoretical value. If the amplitude deviation of the secondary current of each CT and the theoretical value is within ±5% and the phase deviation is within ±2°, proceed to step 10); otherwise, proceed to step 9);

[0049] 9) Confirm that the power supply of the single-phase voltage regulator 10 is turned off, find and eliminate the defects and proceed to step 2);

[0050] 10) The first flow test of the nuclear reactor coolant pump motor is completed.

[0051] The specific process of step 1) is as follows:

[0052] 101) Check and confirm that the main power switch Q1 of the I speed medium voltage switch cabinet 1 has been disconnected and withdrawn for isolation, and check and confirm that the main power switch Q2 of the II speed medium voltage switch cabinet 5 has been disconnected and withdrawn for isolation;

[0053] 102) Check and confirm that the electrical wiring of the primary flow system of the nuclear reactor coolant pump motor is fully connected, and check and confirm that all CT terminal strips are firmly connected;

[0054] 103) Check and confirm that the grounding switch QE1 of the I speed medium voltage switch cabinet 1 is disconnected, and check and confirm that the grounding switch QE2 of the II speed medium voltage switch cabinet 5 is disconnected;

[0055] 104) Check and confirm that the insulation resistance of the primary flow system of the nuclear reactor coolant pump motor meets the requirements.

[0056] In step 8), the theoretical value of each CT secondary current is as follows:

[0057]

[0058]

[0059] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and range of equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0060] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A flow method for a primary flow system of a nuclear reactor coolant pump motor, based on a primary flow system of a nuclear reactor coolant pump motor, comprising a speed I medium-voltage switch cabinet (1), a speed I cable (2), a first electrical penetration piece (3), a speed II medium-voltage switch cabinet (5), a speed II cable (6), a second electrical penetration piece (7), and a nuclear reactor coolant pump motor (9), wherein the speed I medium-voltage switch cabinet (1) is connected to the nuclear reactor coolant pump motor (9) via the speed I cable (2) and the first electrical penetration piece (3), and the speed II medium-voltage switch cabinet (5) is connected to the nuclear reactor coolant pump motor (9) via the speed II cable (6) and the second electrical penetration piece (7); It also includes a speed differential protection relay (4), wherein the current transformer TA7 of the speed medium voltage switch cabinet (1) and the current transformer TA5 of the nuclear reactor coolant pump motor (9) are connected to the speed differential protection relay (4) to form a speed A phase differential protection; the current transformer TA8 of the speed medium voltage switch cabinet (1) and the current transformer TA6 of the nuclear reactor coolant pump motor (9) are connected to the speed differential protection relay (4) to form a speed B phase differential protection; the current transformer TA9 of the speed medium voltage switch cabinet (1) and the current transformer TA4 of the nuclear reactor coolant pump motor (9) are connected to the speed differential protection relay (4) to form a speed C phase differential protection; It also includes a II speed differential protection relay (8), wherein the current transformer TA10 of the II speed medium voltage switch cabinet (5) and the current transformer TA1 of the nuclear reactor coolant pump motor (9) are connected to the II speed differential protection relay (8) to form II speed A phase differential protection; the current transformer TA11 of the II speed medium voltage switch cabinet (5) and the current transformer TA2 of the nuclear reactor coolant pump motor (9) are connected to the II speed differential protection relay (8) to form II speed B phase differential protection; the current transformer TA12 of the II speed medium voltage switch cabinet (5) and the current transformer TA3 of the nuclear reactor coolant pump motor (9) are connected to the II speed differential protection relay (8) to form II speed C phase differential protection; It also includes a single-phase voltage regulator (10), the output terminal of the single-phase voltage regulator (10) being respectively connected to the cable side static contact point A1 of the I speed medium-voltage switch cabinet (1) and the cable connection copper bar point B20 of the II speed medium-voltage switch cabinet (5) when the I speed A phase differential protection is turned on once; the output terminal of the single-phase voltage regulator (10) being respectively connected to the cable side static contact point B1 of the I speed medium-voltage switch cabinet (1) and the cable connection copper bar point C20 of the II speed medium-voltage switch cabinet (5) when the I speed B phase differential protection is turned on once; the output terminal of the single-phase voltage regulator (10) being respectively connected to the cable side static contact point C1 of the I speed medium-voltage switch cabinet (1) and the cable connection copper bar point A20 of the II speed medium-voltage switch cabinet (5) when the I speed C phase differential protection is turned on once; The output terminal of the single-phase voltage regulator (10) is respectively connected to the static contact point A2 of the cable side of the medium-voltage switch cabinet (5) at the speed II and the cable connection copper bar point A10 of the medium-voltage switch cabinet (1) at the speed I when the differential protection of the phase A at the speed II is turned on once; the output terminal of the single-phase voltage regulator (10) is respectively connected to the static contact point B2 of the cable side of the medium-voltage switch cabinet (5) at the speed II and the cable connection copper bar point B10 of the medium-voltage switch cabinet (1) at the speed I when the differential protection of the phase B at the speed II is turned on once; the output terminal of the single-phase voltage regulator (10) is respectively connected to the static contact point C2 of the cable side of the medium-voltage switch cabinet (5) at the speed II and the cable connection copper bar point C10 of the medium-voltage switch cabinet (1) at the speed I when the differential protection of the phase C at the speed II is turned on once; Features: The following steps are involved: Step (1) is to prepare for a flow test of a nuclear reactor coolant pump motor, and after all the preliminary preparations are completed, proceed to step (2); Step (2) performs a primary current flow of the A-phase differential protection at speed I: the output terminal of the single-phase voltage regulator (10) is respectively connected to the cable side static contact point A1 of the speed I medium voltage switch cabinet (1) and the cable connection copper bar point B20 of the speed II medium voltage switch cabinet (5), then the power supply of the single-phase voltage regulator (10) is turned on to pass a primary current of 20A, the secondary current of each CT is measured and recorded, and the power supply of the single-phase voltage regulator (10) is turned off before entering step (3); Step (3) performs a primary current flow of the I speed B phase differential protection: the output terminal of the single-phase voltage regulator (10) is respectively connected to the cable side static contact B1 point of the I speed medium voltage switch cabinet (1) and the cable connection copper bar C20 point of the II speed medium voltage switch cabinet (5), and then the power supply of the single-phase voltage regulator (10) is turned on to pass a primary current of 20A, and the secondary current of each CT is measured and recorded. After the power supply of the single-phase voltage regulator (10) is turned off, the process proceeds to step (4); Step (4) performs a primary current flow of the C-phase differential protection at speed I: the output terminal of the single-phase voltage regulator (10) is respectively connected to the static contact C1 point of the cable side of the medium-voltage switch cabinet (1) at speed I and the cable connection copper bar A20 point of the medium-voltage switch cabinet (5) at speed II, then the power supply of the single-phase voltage regulator (10) is turned on to pass a primary current of 20 A, the secondary current of each CT is measured and recorded, and the power supply of the single-phase voltage regulator (10) is turned off before entering step (5); Step (5) performs a primary current flow of the A-phase differential protection at the speed II: the output terminal of the single-phase voltage regulator (10) is respectively connected to the cable side static contact point A2 of the speed II medium-voltage switch cabinet (5) and the cable connection copper bar point A10 of the speed I medium-voltage switch cabinet (1), and then the power supply of the single-phase voltage regulator (10) is turned on to pass a primary current of 20 A, and the secondary current of each CT is measured and recorded. After the power supply of the single-phase voltage regulator (10) is turned off, the process proceeds to step (6); Step (6) performs a primary current flow of the B-phase differential protection at the speed II: the output terminal of the single-phase voltage regulator 10 is respectively connected to the cable side static contact point B2 of the speed II medium-voltage switch cabinet (5) and the cable connection copper bar point B10 of the speed I medium-voltage switch cabinet (1), then the power supply of the single-phase voltage regulator (10) is turned on to pass a primary current of 20A, the secondary current of each CT is measured and recorded, and the power supply of the single-phase voltage regulator (10) is turned off before entering step (7); Step (7) performs a primary current flow of the C-phase differential protection at the speed II: the output terminal of the single-phase voltage regulator (10) is respectively connected to the static contact C2 point of the cable side of the medium-voltage switch cabinet (5) at the speed II and the cable connection copper bar C10 point of the medium-voltage switch cabinet (1) at the speed I, then the power supply of the single-phase voltage regulator (10) is turned on to pass a primary current of 20 A, the secondary current of each CT is measured and recorded, and the power supply of the single-phase voltage regulator (10) is turned off before entering step (8); Step (8) determines whether the secondary current of each CT is consistent with the theoretical value. If the amplitude deviation of the secondary current of each CT and the theoretical value is within ±5% and the phase deviation is within ±2°, proceed to step (10); otherwise, proceed to step (9); Step (9) confirming that the power supply of the single-phase voltage regulator (10) is turned off, finding and eliminating the defect and then proceeding to step (2); Step (10) The first flow test of the nuclear reactor coolant pump motor is completed.

2. A flow-through method for a primary flow-through system of a nuclear reactor coolant pump motor according to claim 1, characterized in that: The specific process of step (1) is as follows: Step (101) checks and confirms that the main power switch Q1 of the I speed medium voltage switch cabinet (1) has been disconnected and withdrawn for isolation, and checks and confirms that the main power switch Q2 of the II speed medium voltage switch cabinet (5) has been disconnected and withdrawn for isolation; Step (102) checks and confirms that the electrical wiring of the primary flow system of the nuclear reactor coolant pump motor is fully connected, and checks and confirms that all CT terminal strips are firmly connected; Step (103) checks and confirms that the grounding switch QE1 of the I speed medium voltage switch cabinet (1) is disconnected, and checks and confirms that the grounding switch QE2 of the II speed medium voltage switch cabinet (5) is disconnected; Step (104) checks and confirms that the insulation resistance of the primary flow system of the nuclear reactor coolant pump motor meets the requirements.

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