Automatic off-grid and grid-connected control device of fracturing energy storage system

Abstract

The utility model relates to the technical field of oilfield fracturing skid driving, and discloses an automatic off-grid and grid-connected control device for a fracturing energy storage system, which comprises an EMS control cabinet, a fracturing system power supply circuit and a voltage acquisition circuit, according to feedback signals of the high-voltage switch and power grid voltage feedback data, automatic off-grid and grid-connected logic control is achieved, personnel monitoring is reduced, cost is reduced, and reliability is higher.

Description

TECHNICAL FIELD

[0001] The utility model relates to oilfield fracturing skid drive technical field, concretely relates to a fracturing energy storage system automatic off grid control device. BACKGROUND

[0002] Fracturing is a conventional oilfield exploitation method in the middle and later stages of oilfield exploitation, which needs to be manually fractured by workers to reduce the oil output of the oilfield, open the underground rock layer, and improve the oil output of the oilfield. The frequency conversion driven fracturing system is the inevitable development trend of shale energy exploitation equipment. In the fracturing scene, due to insufficient power supply capacity of the power grid, expansion difficulty, unstable power supply and other problems, the user side energy storage system can play a capacity expansion role to provide stable power supply for the fracturing equipment and reduce the cost.

[0003] The main functions of the user side energy storage system are: 1. Fill the valley: during the low valley period, the energy storage system can store excess electricity, fully utilize the low valley electricity price, and reduce the overall electricity cost; 2. Backup power supply: improve the power supply reliability, and when the power grid capacity is insufficient, fails or is powered off, the energy storage system can be used as a backup power supply to ensure the normal operation of key equipment and facilities and improve the power supply reliability. 3. Black start: the energy storage system can provide black start function to help quickly restore power supply after the power grid is completely powered off.

[0004] During the fracturing operation process, the energy storage system can maintain the system voltage at about 10.5kV. Based on the power grid capacity, voltage, load, energy storage SOC and the like, the energy storage power is automatically adjusted in real time to meet the energy consumption of the frequency conversion electric drive pump and the sand mixing pump.

[0005] The fracturing energy storage system operates independently of the external power grid in off-grid mode, mainly relying on its own battery energy storage for power supply output. In this mode, the energy storage system can be used as an independent power supply to provide power support for the sand mixing and pumping devices of the fracturing system, ensuring uninterrupted operation of sand mixing and pumping. In grid-connected mode, the energy storage system is connected to the external power grid, which can discharge to the power grid to power the fracturing system, and also can charge the energy storage system battery from the power grid. However, the existing method usually manually operates the off-grid and grid-connected operation through the touch screen of the EMS system according to whether the voltage of the power grid exists, and cannot realize automatic control. UTILITY MODEL CONTENTS

[0006] In view of the above shortcomings in the prior art, the utility model provides a fracturing energy storage system automatic off-grid and grid-connected control device.

[0007] In order to achieve the above utility model purposes, the utility model adopts the technical scheme that:

[0008] A fracturing energy storage system automatic off-grid and grid-connected control device comprises:

[0009] EMS control cabinet, fracturing system power supply circuit and voltage acquisition circuit;

[0010] The normally open auxiliary contact of the main incoming switch in the power supply circuit of the fracturing system is connected in series with the normally open auxiliary contact of the power supply switch of the fracturing frequency converter, and is connected to the DI input interface of the EMS control cabinet.

[0011] The normally closed auxiliary contact of the main incoming switch in the power supply circuit of the fracturing system is connected in series with the normally closed auxiliary contact of the power supply switch of the fracturing frequency converter, and is connected to the DI input interface of the EMS control cabinet.

[0012] The normally open feedback contact of the undervoltage release device of the main incoming switch in the power supply circuit of the fracturing system is connected in series with the normally open feedback contact of the undervoltage release device of the power supply switch of the fracturing frequency converter, and is connected to the DI input interface of the EMS control cabinet.

[0013] The input terminal of the voltage acquisition circuit is connected to the input terminal of the fracturing system power supply circuit, and the output terminal of the voltage acquisition circuit is connected to the communication interface of the EMS control cabinet.

[0014] Preferably, the power supply circuit of the fracturing system includes:

[0015] The main incoming line switch and at least two power supply switches for the fracturing frequency converters;

[0016] The incoming line contacts of the main incoming line switch are respectively connected to the R-phase terminal, S-phase terminal and T-phase terminal of the power grid;

[0017] The outgoing contacts of the main incoming switch are connected to the incoming contacts of the power supply switches of each fracturing frequency converter.

[0018] Preferably, the voltage acquisition circuit includes:

[0019] First voltage transformer, second voltage transformer, and voltage detection instrument;

[0020] One input terminal of the first voltage transformer is connected to the R-phase terminal of the power grid, the other input terminal of the first voltage transformer is connected to the S-phase terminal of the power grid, and the two output terminals of the first voltage transformer are connected to a voltage detection instrument.

[0021] One input terminal of the second voltage transformer is connected to the other input terminal of the first voltage transformer, the other input terminal of the second voltage transformer is connected to the T-phase terminal of the power grid, and the two output terminals of the second voltage transformer are connected to a voltage detection instrument.

[0022] Preferably, a first fuse is installed between one of the input terminals of the first voltage transformer and the R-phase terminal of the power grid.

[0023] Preferably, a second fuse is provided between the other input terminal of the second voltage transformer and the T-phase terminal of the power grid.

[0024] Preferably, the voltage detection instrument is connected to the communication interface of the EMS control cabinet via an RS485 communication interface.

[0025] This utility model has the following beneficial effects:

[0026] This invention achieves automatic grid connection and disconnection logic control based on feedback signals from high-voltage switches and grid voltage feedback data, reducing personnel monitoring, lowering costs, and increasing reliability. Attached Figure Description

[0027] Figure 1 A schematic diagram of the principle of an automatic grid connection / disconnection control device for a fracturing energy storage system;

[0028] Figure 2 A schematic diagram of an automatic grid connection / disconnection control device for a fracturing energy storage system;

[0029] Figure 3 This is a schematic diagram of an oilfield fracturing energy storage system.

[0030] Figure 4 This is a schematic diagram of the power supply circuit for the fracturing system in an oilfield well site. Detailed Implementation

[0031] The specific embodiments of this utility model are described below to enable those skilled in the art to understand this utility model. However, it should be understood that this utility model is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of this utility model as defined and determined by the appended claims, these changes are obvious. All utility model creations utilizing the concept of this utility model are within the scope of protection.

[0032] Reference Figure 1 and Figure 2 This utility model provides an automatic grid connection / disconnection control device for a fracturing energy storage system, comprising:

[0033] EMS control cabinet, fracturing system power supply circuit and voltage acquisition circuit;

[0034] The normally open auxiliary contact of the main incoming switch in the power supply circuit of the fracturing system is connected in series with the normally open auxiliary contact of the power supply switch of the fracturing frequency converter, and is connected to the DI input interface of the EMS control cabinet.

[0035] The normally closed auxiliary contact of the main incoming switch in the power supply circuit of the fracturing system is connected in series with the normally closed auxiliary contact of the power supply switch of the fracturing frequency converter, and is connected to the DI input interface of the EMS control cabinet.

[0036] The normally open feedback contact of the undervoltage release device of the main incoming switch in the power supply circuit of the fracturing system is connected in series with the normally open feedback contact of the undervoltage release device of the power supply switch of the fracturing frequency converter, and is connected to the DI input interface of the EMS control cabinet.

[0037] The input terminal of the voltage acquisition circuit is connected to the input terminal of the fracturing system power supply circuit, and the output terminal of the voltage acquisition circuit is connected to the communication interface of the EMS control cabinet.

[0038] Reference Figure 3 The oilfield fracturing energy storage system involved in this embodiment mainly consists of the following parts:

[0039] 1. High-voltage switchgear: Controls the opening and closing of the high-voltage side power supply of the step-up transformer;

[0040] 2. Step-up transformer: It raises the AC low voltage of the energy storage system to the voltage level of the power grid and is also an essential configuration for PCS to be connected to or disconnected from the grid.

[0041] 3. PCS: AC-DC bidirectional converter, which realizes bidirectional conversion between AC and DC power, converting AC power into DC power required by the battery, or converting DC power from the battery into AC power;

[0042] 4. Battery compartment: Composed of battery clusters, combiner cabinets, fire suppression system, cooling system, and BMS (Battery Management System) control cabinet, etc.

[0043] 5. EMS Control Cabinet: EMS is short for Energy Management System. It includes a PLC controller, I / O interfaces, communication interfaces, and a touch screen, and is used to monitor, control, and optimize energy use. The EMS system connects to the Battery Management System (BMS) and the Bidirectional Converter (PCS) via CAN or RS485 to automatically control charging, discharging, and grid connection / disconnection.

[0044] Reference Figure 4 The power supply circuit of the well site fracturing system involved in this embodiment mainly consists of the following high-voltage switches:

[0045] 1. Main incoming line switch QF1;

[0046] 2. Power supply switch QF2 for fracturing frequency converter 1;

[0047] 3. Power supply switch QF3 for fracturing frequency converter 2;

[0048] 4. Power supply switch for sand mixing and pumping: QF4;

[0049] 5. Energy storage system power supply switch QF5.

[0050] In this embodiment, the power supply circuit for the fracturing system includes:

[0051] The main incoming line switch and at least two power supply switches for the fracturing frequency converters;

[0052] The incoming line contacts of the main incoming line switch are respectively connected to the R-phase terminal, S-phase terminal and T-phase terminal of the power grid;

[0053] The outgoing contacts of the main incoming switch are connected to the incoming contacts of the power supply switches of each fracturing frequency converter.

[0054] In this embodiment, the incoming main switch QF1, the power supply switch QF2 for fracturing frequency converter 1, and the power supply switch QF3 for fracturing frequency converter 2 in the power supply system are used. The normally open auxiliary contacts QF1a, QF2a, and QF3a of the three switches are connected in series to form a dry contact, which is then connected to the DI input interface of the EMS control cabinet. Thus, the signal from the normally open auxiliary contact of the switch is used to determine whether the high-voltage switch is in the closed state.

[0055] In this embodiment, the incoming main switch QF1, the power supply switch QF2 for fracturing frequency converter 1, and the power supply switch QF3 for fracturing frequency converter 2 in the power supply system are used. The normally closed auxiliary contacts QF1b, QF2b, and QF3b of the three switches are connected in series to form a dry contact, which is then connected to the DI input interface of the EMS control cabinet. Thus, the high-voltage switch is determined to be in the open state based on the signal of the normally closed auxiliary contact of the switch.

[0056] In this embodiment, the main incoming switch QF1, the power supply switch QF2 for fracturing frequency converter 1, and the power supply switch QF3 for fracturing frequency converter 2 in the power supply system are configured with undervoltage release devices and corresponding auxiliary contacts. The normally open feedback contacts QF1c, QF2c, and QF3c of the undervoltage release devices of the three switches are connected in series to form a dry contact, which is connected to the DI input interface of the EMS control cabinet. Thus, the signal from the normally open feedback contact of the undervoltage release device of the switch is used to determine whether the high-voltage switch is experiencing a power grid outage.

[0057] The voltage acquisition circuit in this embodiment includes:

[0058] First voltage transformer, second voltage transformer, and voltage detection instrument;

[0059] One input terminal of the first voltage transformer is connected to the R-phase terminal of the power grid, the other input terminal of the first voltage transformer is connected to the S-phase terminal of the power grid, and the two output terminals of the first voltage transformer are connected to a voltage detection instrument.

[0060] One input terminal of the second voltage transformer is connected to the other input terminal of the first voltage transformer, the other input terminal of the second voltage transformer is connected to the T-phase terminal of the power grid, and the two output terminals of the second voltage transformer are connected to a voltage detection instrument.

[0061] A first fuse is installed between one of the input terminals of the first voltage transformer and the R-phase terminal of the power grid.

[0062] A second fuse is installed between the other input terminal of the second voltage transformer and the T-phase terminal of the power grid.

[0063] The voltage detection instrument is connected to the communication interface of the EMS control cabinet via an RS485 communication interface.

[0064] In this embodiment, a 10kV voltage is taken from the power grid at the incoming terminal of the main incoming switch QF1. The voltage is then connected to a voltage detection instrument U1 via fuses FU1 and FU2 and voltage transformers VT1 and VT2. The real-time voltage data output by the voltage detection instrument U1 is then connected to the communication interface of the EMS control cabinet via an RS485 communication interface. Alternatively, real-time voltage data can be collected by the integrated protection device of the high-voltage switchgear and then connected to the EMS communication interface via an RS485 communication interface. Thus, the presence of voltage at the incoming terminal of the main incoming switch QF1 can be determined based on the voltage data at the incoming terminal of the main incoming switch QF1.

[0065] In this embodiment, the EMS control cabinet obtains the normally open auxiliary contact signal of the switch closing mechanism, the normally open feedback contact signal of the switch's undervoltage trip unit, and the voltage data of the incoming terminal of the main incoming switch QF1 from the power supply circuit and voltage acquisition circuit of the fracturing system. If there is no voltage at the incoming terminal of the main incoming switch QF1, and the normally open feedback contacts of the three switches' undervoltage trip units (QF1c, QF2c, and QF3c) are all in the undervoltage trip state, then the grid connection automatic... Automatic grid-to-off-grid control: If there is no voltage at the incoming terminal of the main incoming switch QF1, and the normally closed auxiliary contacts of the three switches QF1b, QF2b, and QF3b are all in the open state, then the automatic grid-to-off-grid control will not be initiated, but manual control of grid-to-off-grid control via the touch screen is supported; If the 10kV voltage at the incoming terminal of the main incoming switch QF1 is normal, and the normally open auxiliary contacts of the three switches QF1a, QF2a, and QF3a are all in the closed state, then the automatic grid-to-grid control will be initiated.

[0066] This invention achieves automatic grid connection and disconnection logic control based on feedback signals from high-voltage switches and grid voltage feedback data, reducing personnel monitoring, lowering costs, and increasing reliability.

[0067] This utility model uses specific embodiments to illustrate the principle and implementation of the utility model. The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​the utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the utility model. Therefore, the content of this specification should not be construed as a limitation of the utility model.

[0068] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of this invention, and should be understood that the scope of protection of this invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on these technical teachings disclosed in this invention without departing from the essence of this invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. An automatic grid connection / disconnection control device for a fracturing energy storage system, characterized in that, include: EMS control cabinet, fracturing system power supply circuit and voltage acquisition circuit; The normally open auxiliary contact of the main incoming switch in the power supply circuit of the fracturing system is connected in series with the normally open auxiliary contact of the power supply switch of the fracturing frequency converter, and is connected to the DI input interface of the EMS control cabinet. The normally closed auxiliary contact of the main incoming switch in the power supply circuit of the fracturing system is connected in series with the normally closed auxiliary contact of the power supply switch of the fracturing frequency converter, and is connected to the DI input interface of the EMS control cabinet. The normally open feedback contact of the undervoltage release device of the main incoming switch in the power supply circuit of the fracturing system is connected in series with the normally open feedback contact of the undervoltage release device of the power supply switch of the fracturing frequency converter, and is connected to the DI input interface of the EMS control cabinet. The input terminal of the voltage acquisition circuit is connected to the input terminal of the fracturing system power supply circuit, and the output terminal of the voltage acquisition circuit is connected to the communication interface of the EMS control cabinet.

2. The automatic grid connection / disconnection control device for a fracturing energy storage system according to claim 1, characterized in that, The power supply circuit of the fracturing system includes: The main incoming line switch and at least two power supply switches for the fracturing frequency converters; The incoming line contacts of the main incoming line switch are respectively connected to the R-phase terminal, S-phase terminal and T-phase terminal of the power grid; The outgoing contacts of the main incoming switch are connected to the incoming contacts of the power supply switches of each fracturing frequency converter.

3. The automatic grid connection / disconnection control device for a fracturing energy storage system according to claim 1, characterized in that, The voltage acquisition circuit includes: First voltage transformer, second voltage transformer, and voltage detection instrument; One input terminal of the first voltage transformer is connected to the R-phase terminal of the power grid, the other input terminal of the first voltage transformer is connected to the S-phase terminal of the power grid, and the two output terminals of the first voltage transformer are connected to a voltage detection instrument. One input terminal of the second voltage transformer is connected to the other input terminal of the first voltage transformer, the other input terminal of the second voltage transformer is connected to the T-phase terminal of the power grid, and the two output terminals of the second voltage transformer are connected to a voltage detection instrument.

4. The automatic grid connection / disconnection control device for a fracturing energy storage system according to claim 3, characterized in that, A first fuse is installed between one of the input terminals of the first voltage transformer and the R-phase terminal of the power grid.

5. The automatic grid connection / disconnection control device for a fracturing energy storage system according to claim 3, characterized in that, A second fuse is installed between the other input terminal of the second voltage transformer and the T-phase terminal of the power grid.

6. The automatic grid connection / disconnection control device for a fracturing energy storage system according to claim 3, characterized in that, The voltage detection instrument is connected to the communication interface of the EMS control cabinet via an RS485 communication interface.

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