A medium voltage power supply vehicle grid connection test device and test method

Abstract

The present invention discloses a medium-voltage power supply vehicle grid-connected test device, including a 0.4kV diesel generator set, a three-winding step-up transformer, a medium-voltage power supply vehicle to be tested, and a load test cabinet; the 0.4kV diesel generator set is connected to the low-voltage side of the three-winding step-up transformer through a cable; the high-voltage side of the three-winding step-up transformer is connected to the mains input side of the switch cabinet of the medium-voltage power supply vehicle to be tested through a cable; the load output end of the medium-voltage power supply vehicle to be tested is connected to the load test cabinet through a cable. The present invention can simulate the power supply of a 10kV distribution network line to avoid impacting the distribution network line; by adjusting the operating parameters such as voltage, phase sequence, frequency, etc. of the grid-connected test device and manually setting the fault operating conditions, the grid-connected function and product performance of the medium-voltage power supply vehicle can be verified. The present invention has simple structure and components, is practical, has strong versatility, and has high testing efficiency.

Description

Technical Field

[0001] The invention relates to the field of emergency power supply vehicles, and in particular to a grid-connected testing device and a testing method for a medium-voltage power supply vehicle. Background Art

[0002] At present, natural disasters occur frequently in my country, external force damage occurs from time to time, the risk of large-scale power outages still exists, and power production safety accidents have not been effectively eliminated. The medium-voltage power supply vehicle adopts 10kV distribution network lines for power supply, which has the characteristics of longer transmission distance and larger power supply load, and is widely used in power supply security of the power department. At the same time, the medium-voltage power supply vehicle also has the function of connecting to the mains, which can realize the uninterrupted switching of the power supply of the medium-voltage power supply vehicle and the mains, ensuring that users who are undergoing planned maintenance can operate without power outages.

[0003] In order to improve the technical level of medium-voltage power supply vehicles and ensure the safety of medium-voltage power supply vehicles and distribution networks, the grid-connected testing technology of medium-voltage power supply vehicles has gradually received attention. my country has conducted relevant research on the grid-connected technology of medium-voltage power supply vehicles and formulated corresponding standards, requiring medium-voltage power supply vehicles to conduct adaptability tests such as voltage, frequency, phase sequence, phase, base load, etc. when connected to the grid, and meet other grid-connected technical requirements.

[0004] Based on the operational safety considerations of the 10kV distribution network, the power department strictly prohibits medium-voltage power supply vehicle manufacturers from conducting grid-connected tests privately to avoid 10kV distribution network operation failures caused by quality problems of medium-voltage power supply vehicles. However, due to the consideration of distribution network operation safety, the grid-connected test of medium-voltage power supply vehicles cannot be carried out in the distribution network line; and using two medium-voltage power supply vehicles of the same voltage level (one simulating the mains) for testing, it is difficult to simulate the actual distribution network line connection because the voltage, frequency, generator power, and generator winding are the same. Therefore, a universal grid-connected test device is needed as a test tool for the factory test of medium-voltage power supply vehicles and the acceptance of medium-voltage power supply vehicles by power departments. Summary of the invention

[0005] The purpose of the present invention is to provide a practical and effective grid-connected test device and test method, which can simulate the power supply of a 10kV distribution network line and avoid impact on the distribution network line.

[0006] The technical problem solved by the present invention can be achieved by adopting the following technical solutions:

[0007] A medium-voltage power supply vehicle grid-connected test device comprises a 0.4kV diesel generator set, a three-winding step-up transformer, a medium-voltage power supply vehicle to be tested and a load test cabinet; the medium-voltage power supply vehicle to be tested is provided with a switch cabinet, the 0.4kV diesel generator set is connected to the low-voltage side of the three-winding step-up transformer through a cable; the high-voltage side of the three-winding step-up transformer is connected to the mains input side of the switch cabinet of the medium-voltage power supply vehicle to be tested through a cable; the load output end of the medium-voltage power supply vehicle to be tested is connected to the load test cabinet through a cable.

[0008] Preferably, the 0.4kV diesel generator set is used to simulate mains electricity and is provided with a set controller for protection control. The set controller controls the output power frequency of the 0.4kV diesel generator set through a speed regulator and controls the output power voltage of the generator set through a voltage regulator controller.

[0009] Preferably, the medium-voltage power supply vehicle to be tested is composed of an oil engine input cabinet, a load output cabinet, a mains input cabinet, and a PT cabinet, and is provided with a 901 vacuum switch, a load output port, a 902 vacuum switch and a mains input port.

[0010] Preferably, the load test cabinet is connected to an industrial computer via a PLC controller, and the special software of the industrial computer realizes the control of the division and addition of each load power level. The industrial computer realizes I0 quantity control through the PLC controller, and the I0 quantity controls the load power of each level.

[0011] A method for testing the rated voltage and frequency of a medium voltage power supply vehicle, comprising the following steps:

[0012] Step 1: Start, start the 0.4kV diesel generator set, and boost the 0.4kV power supply to 10kV through a three-winding step-up transformer;

[0013] Step 2: Forward grid connection (medium voltage power supply vehicle and mains are connected in parallel), ① 902 vacuum switch is closed, mains input and load output busbars are turned on, and power is supplied to the load test cabinet; ② The load test cabinet is loaded with load power P, and at this time, the load test cabinet load power P is fully borne by the 0.4kV diesel generator set; ③ The base load power P1 of the unit controller of the medium voltage power supply vehicle, P1 is less than P; ④ Start the generator set of the medium voltage power supply vehicle, trigger the closing signal of the 901 vacuum switch, and the unit controller first detects the voltage, frequency, phase sequence, phase angle and other power parameters on the mains input side, and completes the synchronization with the mains input side power supply through the speed controller, voltage regulator and other devices, and sends the closing signal of the 901 vacuum switch for forward grid connection; ⑤ After the medium voltage power supply vehicle is connected to the grid, it is flexibly loaded to the base load power P1, and the load test cabinet is loaded with load power P= P1+ P2, where P2 is the load power of the 0.4kV diesel generator set;

[0014] Step 3: Mains disconnection, ① Open the 902 vacuum switch to disconnect the simulated mains. ② The medium-voltage power supply vehicle switches from grid-connected to island operation, P = P3, P3 is the load output power of the medium-voltage power supply vehicle, P3 is greater than P1;

[0015] Step 4: Reverse grid connection (mains power and medium-voltage power supply vehicle are connected in parallel), ① trigger the 902 vacuum switch closing signal, the unit controller first detects the voltage, frequency, phase sequence, phase angle and other power parameters on the mains input side, and completes the synchronization with the mains input side power supply through the speed controller, voltage regulator and other devices, and sends the 902 vacuum switch closing signal for reverse grid connection; ② after the mains power is connected to the grid, the medium-voltage power supply vehicle flexibly reduces the load to the base load power P1, and the load test cabinet loads the load power P = P1 + P2, P2 is the load power of the 0.4kV diesel generator set;

[0016] Step 5: After the test is completed, ① open the 901 vacuum switch, de-energize the medium-voltage power supply vehicle, and stop the generator set of the medium-voltage power supply vehicle; ② load the load power P= P2 to the load test cabinet, where P2 is the load power of the 0.4kV diesel generator set; open the 902 vacuum switch and stop the 0.4kV diesel generator set.

[0017] Preferably, the rated voltage ±10% grid-connected test includes the following steps: ① Start the 0.4kV diesel generator set, adjust the voltage regulator controller so that the 10kV power supply of the three-winding step-up transformer is 10% higher than the rated voltage; ② Perform an operation test according to steps 2 to 5; ③ Start the 0.4kV diesel generator set, adjust the voltage regulator controller so that the 10kV power supply of the three-winding step-up transformer is 10% lower than the rated voltage; ④ Perform an operation test according to steps 2 to 5.

[0018] Preferably, the rated voltage ±5% grid-connected test includes the following steps: ① starting the 0.4kV diesel generator set, adjusting the speed controller so that the frequency of the three-winding step-up transformer is 5% higher than the rated frequency; ② performing an operation test according to steps 2 to 5; ③ starting the 0.4kV diesel generator set, adjusting the speed controller so that the frequency of the three-winding step-up transformer is 5% lower than the rated frequency; ④ performing an operation test according to steps 2 to 5.

[0019] The grid-connected test device of the present invention can simulate the power supply of a 10kV distribution network line to avoid impact on the distribution network line; by adjusting the voltage, phase sequence, frequency and other working condition parameters of the grid-connected test device and manually setting the fault condition, the grid-connected function and product performance of the medium-voltage power supply vehicle can be verified; by adjusting the 0.4kV diesel generator set, the voltage and frequency after boosting can be controlled. At the same time, the grid-connected test device can provide practical training and exercises for operators, and provide technical verification for the actual grid connection of the medium-voltage power supply vehicle to the 10kV distribution network line. The test device of the present invention has a simple structure and components, is practical, has strong versatility, and has high testing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of module connection of the present invention.

[0021] Figure 2 It is a schematic diagram of the composition of the switch cabinet of the medium-voltage power supply vehicle to be tested of the present invention.

[0022] Figure 3 It is a test flow chart of the present invention. DETAILED DESCRIPTION

[0023] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments, but the embodiments of the present invention are not limited thereto.

[0024] Figures 1 to 3 It is a preferred solution of the present invention, comprising a 0.4kV diesel generator set, a three-winding step-up transformer, a medium-voltage power supply vehicle to be tested and a load test cabinet. The medium-voltage power supply vehicle to be tested is provided with a switch cabinet, the 0.4kV diesel generator set is connected to the low-voltage side of the three-winding step-up transformer through a cable; the high-voltage side of the three-winding step-up transformer is connected to the mains input side of the switch cabinet of the medium-voltage power supply vehicle to be tested through a cable; the load output end of the medium-voltage power supply vehicle to be tested is connected to the load test cabinet through a cable.

[0025] The 0.4kV diesel generator set is used to simulate the mains power supply and is equipped with a unit controller for protection control. The unit controller controls the output power frequency of the generator set through the speed governor and controls the output power voltage of the generator set through the voltage regulator.

[0026] The 0.4kV diesel generator power supply is boosted by a three-winding step-up transformer, which boosts 0.4kV to 10kV. The three-winding step-up transformer has a fixed winding ratio. When the input voltage increases or decreases, the high-voltage side of the boost changes with the ratio. The diesel generator set boosted to 10kV is protected and controlled by the unit controller. The unit controller controls the output power frequency of the generator set through the speed governor, controls the output power voltage of the generator set through the voltage regulator, and realizes the switching and power measurement of each bus through the switch cabinet.

[0027] The switch cabinet of the medium-voltage power supply vehicle to be tested consists of an oil engine input cabinet, a load output cabinet, a mains input cabinet, and a PT cabinet, and is equipped with a 901 vacuum switch, a load output port, a 902 vacuum switch, and a mains input port. The oil engine input cabinet is connected to the voltage output end of the 10kV diesel generator set, and the mains input cabinet is connected to the high-voltage side of the three-winding step-up transformer; the load output cabinet is connected to the load test cabinet. The PT cabinet is a voltage transformer cabinet, including a PT1 voltage transformer installed on the oil engine input bus and a PT2 voltage transformer installed on the mains input bus, which is used to detect the bus voltage of the oil engine input and the mains input to achieve the protection function.

[0028] The load test cabinet is connected to an industrial computer through a PLC controller, and the special software of the industrial computer realizes the division and addition control of each load power gear. The industrial computer realizes I0 quantity control through PLC, and I0 quantity controls the load power of each gear.

[0029] The rated voltage and frequency grid-connected test operation method is as follows:

[0030] Step 1: Start, start the 0.4kV diesel generator set, and boost the 0.4kV power supply to 10kV through a three-winding step-up transformer.

[0031] Step 2: Forward grid connection (medium voltage power supply vehicle and mains are connected in parallel), ① 902 vacuum switch is closed, mains input and load output busbars are turned on, and power is supplied to the load test cabinet. ② The load test cabinet is loaded with load power P. At this time, the load power P of the load test cabinet is fully borne by the 0.4kV diesel generator set. ③ The base load power P1 of the unit controller of the medium voltage power supply vehicle is P1, and P1 is less than P. ④ Start the generator set of the medium voltage power supply vehicle, trigger the closing signal of the 901 vacuum switch, and the unit controller first detects the voltage, frequency, phase sequence, phase angle and other power parameters on the mains input side, and completes the synchronization with the mains input side power supply through the speed controller, voltage regulator and other devices, and sends the closing signal of the 901 vacuum switch for forward grid connection. ⑤ After the medium voltage power supply vehicle is connected to the grid, it is flexibly loaded to the base load power P1, and the load test cabinet is loaded with load power P= P1+ P2, where P2 is the load power of the 0.4kV diesel generator set.

[0032] Step 3: Mains disconnection, ① Open 902 vacuum switch to simulate mains disconnection. ② The medium voltage power supply vehicle switches from grid connection to island operation, P = P3, P3 is the load output power of the medium voltage power supply vehicle, P3 is greater than P1.

[0033] Step 4: Reverse grid connection (mains power and medium-voltage power supply vehicle in parallel), ① trigger the 902 vacuum switch closing signal, the unit controller first detects the voltage, frequency, phase sequence, phase angle and other power parameters on the mains input side, and completes the synchronization with the mains input side power supply through the speed controller, voltage controller and other devices, and sends the 902 vacuum switch closing signal for reverse grid connection. ② After the mains power is connected to the grid, the medium-voltage power supply vehicle flexibly reduces the load to the base load power P1, and the load test cabinet loads the load power P = P1 + P2, where P2 is the load power of the 0.4kV diesel generator set.

[0034] Step 5: After the test is completed, ① Open the 901 vacuum switch, de-energize the medium-voltage power supply vehicle, and stop the generator set of the medium-voltage power supply vehicle. ② Load the load power P= P2 in the load test cabinet, where P2 is the load power of the 0.4kV diesel generator set. Open the 902 vacuum switch and stop the 0.4kV diesel generator set.

[0035] The rated voltage (±10%) grid-connected test operation method is as follows:

[0036] ① Start the 0.4kV diesel generator set and adjust the voltage regulator so that the 10kV power supply of the three-winding step-up transformer is 10% higher than the rated voltage. ② Perform the operation test according to steps 2 to 5 of the rated voltage and frequency grid-connected test operation method. ③ Start the 0.4kV diesel generator set and adjust the voltage regulator so that the 10kV power supply of the three-winding step-up transformer is 10% lower than the rated voltage. ④ Perform the operation test according to steps 2 to 5 of the rated voltage and frequency grid-connected test operation method.

[0037] The rated frequency (±5%) grid-connected test operation method is as follows:

[0038] ① Start the 0.4kV diesel generator set and adjust the speed controller so that the frequency of the three-winding step-up transformer is 5% higher than the rated frequency; ② Perform the operation test according to steps 2 to 5 of the rated voltage and frequency grid-connected test operation method. ③ Start the 0.4kV diesel generator set and adjust the speed controller so that the frequency of the three-winding step-up transformer is 5% lower than the rated frequency; ④ Perform the operation test according to steps 2 to 5 of the rated voltage and frequency grid-connected test operation method.

[0039] The above description is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any slight modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the present invention.

Claims

1. A test method for a medium voltage power supply vehicle grid-connected test device, Features: The medium-voltage power supply vehicle grid-connected test device comprises a 0.4kV diesel generator set, a three-winding step-up transformer, a medium-voltage power supply vehicle to be tested and a load test cabinet; the medium-voltage power supply vehicle to be tested is provided with a switch cabinet, and the 0.4kV diesel generator set is connected to the low-voltage side of the three-winding step-up transformer through a cable; the high-voltage side of the three-winding step-up transformer is connected to the mains input side of the switch cabinet of the medium-voltage power supply vehicle to be tested through a cable; the 0.4kV diesel generator set is used to simulate the mains, and is provided with a unit controller for protection control, and the unit controller controls the output power frequency of the 0.4kV diesel generator set through a speed regulator, and controls the output power frequency of the generator set through a voltage regulator controller. pressure; the load output end of the medium-voltage power supply vehicle to be tested is connected to the load test cabinet through a cable; the medium-voltage power supply vehicle to be tested is composed of an oil engine input cabinet, a load output cabinet, a mains input cabinet, and a PT cabinet, and is provided with a 901 vacuum switch, a load output port, a 902 vacuum switch and a mains input port; the PT cabinet includes a PT1 voltage transformer installed on the oil engine input bus and a PT2 voltage transformer installed on the mains input bus; the load test cabinet is connected to an industrial computer through a PLC controller, and the industrial computer special software realizes the split and input control of each load power gear, and the industrial computer realizes I0 quantity control through the PLC controller, and the I0 quantity controls the load power of each gear; The test method is a method for performing a grid-connected test of a medium-voltage power supply vehicle at a rated voltage and frequency by a grid-connected test device for the medium-voltage power supply vehicle, comprising the following steps: Step 1: Start, start the 0.4kV diesel generator set, and boost the 0.4kV power supply to 10kV through a three-winding step-up transformer; Step 2: Forward grid connection, ① 902 vacuum switch is closed, the mains input and load output busbars are turned on, and power is supplied to the load test cabinet; ② The load test cabinet is loaded with load power P, and the load power P of the load test cabinet is fully borne by the 0.4kV diesel generator set at this time; ③ The base load power P1 of the unit controller of the medium-voltage power supply vehicle, P1 is less than P; ④ Start the generator set of the medium-voltage power supply vehicle, trigger the closing signal of the 901 vacuum switch, the unit controller first detects the mains input power parameters, and completes the synchronization with the mains input side power supply through the speed controller and the voltage controller, and sends the closing signal of the 901 vacuum switch for forward grid connection; ⑤ After the medium-voltage power supply vehicle is connected to the grid, it is flexibly loaded to the base load power P1, and the load test cabinet is loaded with load power P=P1+P2, where P2 is the load power of the 0.4kV diesel generator set; Step 3: Mains disconnection: ① Open the 902 vacuum switch to simulate mains disconnection; ② The medium-voltage power supply vehicle switches from grid-connected operation to island operation, P=P3, P3 is the load output power of the medium-voltage power supply vehicle, and P3 is greater than P1; Step 4: Reverse grid connection, ① trigger the 902 vacuum switch closing signal, the unit controller first detects the mains power parameters, completes the synchronization with the mains input side power supply through the speed controller and voltage controller, and sends the 902 vacuum switch closing signal for reverse grid connection; ② After the mains grid connection, the medium-voltage power supply vehicle flexibly reduces the load to the base load power P1, and the load test cabinet loads the load power P=P1+P2, where P2 is the load power of the 0.4kV diesel generator set; Step 5: After the test is completed, ① open the 901 vacuum switch, de-energize the medium-voltage power supply vehicle, and stop the generator set of the medium-voltage power supply vehicle; ② load the load test cabinet with load power P=P2, where P2 is the load power of the 0.4kV diesel generator set; open the 902 vacuum switch and stop the 0.4kV diesel generator set.

2. A testing method for a medium voltage power supply vehicle grid-connected testing device according to claim 1, Features: The rated voltage ±10% grid connection test includes the following steps: ① Start the 0.4kV diesel generator set and adjust the voltage regulator to make the 10kV power supply of the three-winding step-up transformer higher than the rated voltage by 10%; ② Perform the operation test according to steps 2 to 5; ③ Start the 0.4kV diesel generator set and adjust the voltage regulator to make the 10kV power supply of the three-winding step-up transformer lower than the rated voltage by 10%; ④ Perform the operation test according to steps 2 to 5.

3. The testing method of the medium voltage power supply vehicle grid-connected testing device according to claim 1, Features: The rated voltage ±5% grid connection test includes the following steps: ① Start the 0.4kV diesel generator set and adjust the speed controller so that the frequency of the three-winding step-up transformer is 5% higher than the rated frequency; ② Perform an operation test according to steps 2 to 5; ③ Start the 0.4kV diesel generator set and adjust the speed controller so that the frequency of the three-winding step-up transformer is 5% lower than the rated frequency; ④ Perform an operation test according to steps 2 to 5.

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