Checking method for preventing cross wiring of power supply loop of-48V direct-current communication power supply system

Abstract

The invention relates to the field of electric power supply systems, and discloses a checking method for preventing cross wiring of a power supply loop of a-48V direct current communication power supply system. Aiming at the working characteristics of the station-48V direct current communication power supply system, the invention provides a detection method for quickly, clearly and accurately detecting whether the power supply wiring of the station-48V direct current communication power supply system has cross hidden dangers or not for field maintenance operators, so that the problems existing in early-stage construction and acceptance inspection can be quickly found; the problem that relay protection and automatic devices are forced to stop due to the fact that cable core wires led out of the power source positive electrode (0V) of a communication power source system intersect is comprehensively solved, the reliability of relay protection operation is improved, and safe and stable operation of power grid relay protection is guaranteed.

Description

Technical Field

[0001] The invention patent relates to the field of electric power supply systems and discloses a method for checking the anti-cross wiring of the power supply circuit of a -48V DC communication power supply system. Background Art

[0002] In the power system, relay protection and its automatic devices are the most effective and important means to ensure the stability of the system and the safety of power equipment. It is stipulated that: no power equipment is allowed to be put into operation without relay protection. The plant-station -48V DC communication power supply system is the working power supply for the communication interface equipment of the relay protection and its automatic devices. It usually adopts a dual-set DC system redundant configuration. It has certain particularities compared with the conventional DC220V power supply system. The positive pole (0V) of the power supply system is directly connected to the public busbar, and its negative pole (-48V) is controlled by the single-pole circuit breaker on the DC feeder panel of the power supply system. Its working principle is shown in Figure 1 . During the construction, commissioning and acceptance of the power supply system, people usually refer to the operating methods of conventional DC systems and use the "pulling method" to verify the correspondence between power supply and load. The -48V DC communication power supply system of the plant station has a large load, and there is no problem with the "pulling method" for conventional power outage and power supply operations. However, the "pulling method" and potential detection method can only verify the correspondence between the negative pole of the power supply (-48V) and the load, and cannot detect the error of cross-wiring of the positive pole (0V) lead-out cable core wires of multiple devices. During the transformation of the communication power supply system, if one power supply system is operating normally and the other power supply system is shut down for maintenance as planned, when the DC positive pole (0V) lead-out line on the common busbar of the power supply system is removed, due to the lack of effective detection methods, it often causes unexpected power outages in the protection communication interface equipment in operation, resulting in the forced shutdown of the power system relay protection and its automatic devices, which seriously threatens the safety and stable operation of the system. See Figure 2 .

[0003] On March 25, 2019, the 36th issue of "Communication Power Technology" published a related document "Cutover Method and Case Analysis of Communication DC 48V Power Supply and Its Distribution System", which put forward useful insights into the cutover method of 48V DC power supply distribution system, the risks and coping strategies, such as: "The relevant standards must be followed during the cutover operation, that is, the voltage must be tested before power is taken, and the current must be measured before power is turned off.", "Before removing the cable, the current must be measured to confirm that it is the correct terminal or cable, and the principle of lower level first and higher level second must be followed. When connecting the cable, the positive cable should be connected first and then the negative cable. When removing the cable, the negative cable should be removed first and then the positive cable.", "The human factor risk is mainly the cutover accident caused by the construction personnel's misoperation, which is not uncommon. If an error occurs during the cutover, the cutover can basically be declared a failure. The way to avoid this risk is that the construction personnel must be familiar with the cutover plan before the cutover to ensure that the cutover personnel operate correctly.".

[0004] This article does not provide a specific effective detection method for the cutover of the communication power supply and its distribution system, especially for the inspection method to prevent cross wiring when removing the DC positive (0V) lead wire on the common busbar of the power supply system, thereby avoiding unexpected power outages of the protective communication interface equipment in operation.

[0005] Due to the particularity of the working principle of the -48V DC communication power supply system of the plant station, the current conventional test methods cannot clearly and intuitively detect the corresponding relationship between the positive pole (0V) of the power supply lead cable core wire and the load of the dual power supply system, which brings great confusion to the normal operation of the on-site maintenance personnel and also brings great hidden dangers to the safe and stable operation of the power grid relay protection. Therefore, a -48V DC communication power supply system power circuit anti-cross wiring inspection method is urgently needed on site. Summary of the invention

[0006] The purpose of the present invention is to solve the shortcomings of the prior art. According to the working characteristics of the plant-48V DC communication power supply system, a detection method for quickly, clearly and accurately detecting whether there are cross-hidden dangers in the power wiring of the plant-48V DC communication power supply system is provided for on-site maintenance personnel, so as to quickly discover the problems existing in the early construction and acceptance, and completely eliminate the problem that the relay protection and automatic device are forced to stop operating due to the crossing of the core wires of the cable leading to the positive pole (0V) of the communication power supply system, improve the reliability of the relay protection operation, and provide a -48V DC communication power supply system power circuit anti-cross wiring inspection method.

[0007] The technical solution proposed by the present invention is implemented as follows: a method for checking the anti-cross wiring of the power supply circuit of a -48V DC communication power supply system. The -48V DC communication power supply system of the present invention adopts a double set of DC power supply system redundant configuration, and the method comprises:

[0008] Step 1: Find the connection line 1-2 between the DC positive pole (0V) of the first communication power distribution panel and the positive pole of the first power supply of the communication interface panel on the common busbar of the dual power supply system;

[0009] Step 2: Find the connection line 2-2 between the DC positive pole (0V) of the second communication power distribution panel and the positive pole of the power supply line II of the communication interface panel on the common busbar of the dual power system;

[0010] Step 3: Connect ammeter 1 to connecting line 1-2, and connect ammeter 2 to connecting line 2-2;

[0011] Step 4: Use the pull-through method to read the detection current displayed on ammeter 1 and ammeter 2 respectively. According to the detection current, determine whether the wiring of the positive pole (0V) end of the power supply of channel I and the positive pole (0V) end of the power supply of channel II of each communication interface device is correct or not:

[0012] Ammeter reading situation 1: Ammeter 1 detects current Im≤50mA, and ammeter 2 detects current Im>50mA; channel 1 protection interface device is in shutdown state, that is, the -48V power supply end of channel 1 protection interface device is disconnected, and the cable core wire from the positive pole (0V) end of I power supply is connected to the positive pole (0V) end of channel 1 protection interface device; the -48V power supply end of channel 2 protection interface device is connected to the power supply end normally, and the cable core wire from the positive pole (0V) end of II power supply is connected to the positive pole (0V) end of channel 2 protection interface device, power channel 2 is in operation, and the power supply circuit wiring is correct;

[0013] Ammeter reading situation 2: Ammeter 1 detects current Im≥50mA, ammeter 2 detects current Im<50mA; channel 1 protection interface device is in shutdown state, that is, channel 1 protection interface device

[0014] The -48V power supply terminal has been disconnected, and the cable core wire from the positive (0V) terminal of power supply I is connected to the positive (0V) terminal of the protection interface device of channel 2; the -48V power supply terminal of the protection interface device of channel 2 is connected to the power supply terminal normally, and the cable core wire from the positive (0V) terminal of power supply II is connected to the positive (0V) terminal of the protection interface device of channel 1. The wiring of the positive (0V) terminal of power supply I and the positive (0V) terminal of power supply II is incorrect, and there is cross wiring.

[0015] The ammeter 1 and ammeter 2 used are DC clamp ammeters, and the range of the DC clamp ammeter is 1mA-20A.

[0016] There are multiple communication equipment power circuits connected to the dual DC power supply system, and the inspection method for preventing cross wiring of other communication equipment power circuits is consistent with the four steps described in claim 1.

[0017] The inspection method for preventing cross wiring of the power circuit of a -48V DC communication power system provided by the present invention fully combines the power consumption characteristics of the working state of the communication interface equipment, adopts a DC clamp-type ammeter (0mA-20A) to detect the load current of each lead-out line of the DC positive pole (0V) on the common busbar of the power system, and quantitatively analyzes the accurate correspondence between the power circuit of the communication equipment and the load through judging the load current of each lead-out line of the DC positive pole (0V), which can effectively prevent the occurrence of "accidental contact" and "accidental connection (disconnection) of wires" in on-site operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the power circuit of the DC 48V communication power system;

[0019] Figure 2 This is a schematic diagram of the DC communication power system circuit with cross wiring;

[0020] Figure 3 This is a schematic diagram of on-site detection when wiring is correct;

[0021] Figure 4 This is a schematic diagram of on-site detection during cross wiring.

[0022] In the figure: SDH is the optical transmission equipment; K is the power circuit breaker of the communication interface device (double pole); 23Z and 33Z are the feeder circuit breakers of the communication power distribution panel (single pole); Figure 1 The 4 "communication interface devices" in Figure 3 "Protection channel 1(2) communication interface device" in. DETAILED DESCRIPTION

[0023] During construction commissioning, acceptance and on-site maintenance, the above technology is used to detect the load current of each lead-out line of the DC positive pole (0V) on the common busbar of the power supply system by combining the power-off / power-on operation of the communication equipment with a DC clamp-type ammeter (1mA-20A):

[0024] (1) Correct wiring, see Figure 3 If the channel 1 protection interface device is in the shutdown (maintenance) state and the channel 2 protection interface device is in the running state, then the clamp ammeter 1 has almost no reading, and the detection current Im≤50mA, and the clamp ammeter 2 has readings, and the detection current Im≥50mA;

[0025] (2) Incorrect wiring, see Figure 4 If the channel 1 protection interface device is in the shutdown (maintenance) state and the channel 2 protection interface device is in the operation state, the clamp ammeter 1 has a reading, and the detection current Im≥50mA, and the clamp ammeter 2 has almost no reading, and the detection current Im≤50mA.

Claims

1. A method for checking the cross-wiring prevention of the power supply circuit of a -48V DC communication power supply system. The -48V DC communication power supply system of the present invention adopts a double set of DC power supply system redundant configuration, characterized in that: The method comprises: Step 1: Find the connection line 1-2 between the DC positive pole (0V) of the first communication power distribution panel and the positive pole of the first power supply of the communication interface panel on the common busbar of the dual power supply system; Step 2: Find the connection line 2-2 between the DC positive pole (0V) of the second communication power distribution panel and the positive pole of the power supply line II of the communication interface panel on the common busbar of the dual power system; Step 3: Connect ammeter 1 to connecting line 1-2, and connect ammeter 2 to connecting line 2-2; Step 4: Use the pull-through method to read the detection current displayed on ammeter 1 and ammeter 2 respectively. According to the detection current, determine whether the wiring of the positive pole (0V) end of the power supply of channel I and the positive pole (0V) end of the power supply of channel II of each communication interface device is correct or not: Ammeter reading situation 1: Ammeter 1 detects current Im≤50mA, and ammeter 2 detects current Im>50mA; channel 1 protection interface device is in shutdown state, that is, the -48V power supply end of channel 1 protection interface device is disconnected, and the cable core wire from the positive pole (0V) end of I power supply is connected to the positive pole (0V) end of channel 1 protection interface device; the -48V power supply end of channel 2 protection interface device is connected to the power supply end normally, and the cable core wire from the positive pole (0V) end of II power supply is connected to the positive pole (0V) end of channel 2 protection interface device, power channel 2 is in operation, and the power supply circuit wiring is correct; Ammeter reading situation 2: Ammeter 1 detects current Im≥50mA, ammeter 2 detects current Im<50mA; channel 1 protection interface device is in shutdown state, that is, the -48V power supply terminal of channel 1 protection interface device is disconnected, and the cable core wire from the positive pole (0V) terminal of I power supply is connected to the positive pole (0V) terminal of channel 2 protection interface device; the -48V power supply terminal of channel 2 protection interface device is connected to the power supply terminal normally, and the cable core wire from the positive pole (0V) terminal of II power supply is connected to the positive pole (0V) terminal of channel 1 protection interface device, the wiring of the positive pole (0V) terminal of I power supply and the positive pole (0V) terminal of II power supply are wrong, and there is cross wiring.

2. According to claim 1, a method for checking the anti-cross wiring of the power supply circuit of a -48V DC communication power supply system is characterized in that: The ammeter 1 and ammeter 2 used are DC clamp ammeters, and the range of the DC clamp ammeter is 1mA-20A.

3. The method for checking the anti-cross wiring of the power supply circuit of a -48V DC communication power supply system according to claim 1 is characterized in that: There are multiple communication equipment power circuits connected to the dual DC power supply system, and the inspection method for preventing cross wiring of other communication equipment power circuits is consistent with the four steps described in claim 1.

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