FPSO power system grounding configuration method

Abstract

The invention discloses an FPSO (Floating Production Storage and Offloading) power system grounding configuration method, which comprises the following steps of: setting parameters of a grounding transformer and a grounding resistor according to the magnitude of the capacitance current of a power grid of an FPSO power system; according to the type of the FPSO power system, a high-voltage distribution board and a marine medium-voltage distribution board in the FPSO power system are connected with a grounding transformer, and a neutral point of a production high-voltage transformer is connected with a grounding resistor; determining a control mode between the distribution board and the grounding transformer according to the connection mode among the distribution board, the high-voltage transformer and the grounding transformer; and determining a grounding mode according to the type of the FPSO power system. After the high-resistance grounding system is adopted, redundant charges accumulated during short circuit can be discharged through the grounding transformer and the grounding resistor when a short-circuit fault occurs in a middle-high voltage power system, so that very high oscillation overvoltage possibly occurring in a ground insulation system can be prevented, and equipment of the power system is protected from being damaged.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a grounding configuration method for an FPSO power system. Background Art

[0002] With the deepening of offshore oil and gas field development, FPSO, as one of the important facilities for offshore oil production, has a power system whose stability directly affects the safety of production and life. Traditional power systems usually use a neutral point direct grounding method, but on a special floating platform like FPSO, considering the mobility of the equipment and the complex offshore environment, a high-resistance grounding system becomes a more reasonable choice.

[0003] Common grounding methods in FPSO power systems include neutral point non-effective grounding systems, which can reduce grounding short-circuit currents and prevent damage to equipment caused by excessive oscillation overvoltages caused by short circuits. However, in actual applications, since FPSO power systems involve multiple voltage levels (such as high-voltage 13.8KV systems, marine medium-voltage 6.6KV systems, production medium-voltage 6.6KV systems, and marine / production low-voltage systems), how to reasonably configure grounding transformers and grounding resistors according to the characteristics of different voltage levels and different operating modes of FPSO to ensure the stability and safety of the power system has become an urgent problem to be solved. Summary of the invention

[0004] The object of the present invention is to provide a grounding configuration method for an FPSO power system to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a grounding configuration method for an FPSO power system, the grounding configuration method comprising: The parameters of the grounding transformer and grounding resistance are set according to the grid capacitance current of the FPSO power system; According to the type of the FPSO power system, the high-voltage switchboard and the marine medium-voltage switchboard in the FPSO power system are connected to the grounding transformer, and the neutral point of the production high-voltage transformer is connected to the grounding resistor; Determine the control mode between the power distribution board and the grounding transformer according to the connection mode between the power distribution board, the high voltage transformer and the grounding transformer; According to the type of FPSO power system, the grounding method is determined as follows: When the FPSO power system is a high voltage system, the high voltage switchboard is electrically connected to the grounding transformer; When the FPSO power system is a marine medium voltage system, the marine medium voltage switchboard is electrically connected to the grounding transformer; When the FPSO power system is a production medium voltage system, the neutral point of the production high voltage transformer is electrically connected to the grounding resistor; When the FPSO power system is a marine / production low voltage system, the low voltage switchboard is electrically connected to the power grounding system which is insulated from the ground.

[0006] Furthermore, the neutral point-to-ground current of the FPSO power system is greater than the grid capacitance current of the FPSO power system.

[0007] Furthermore, the connection method between the high-voltage switchboard, the marine medium-voltage switchboard and the marine high-voltage transformer, the grounding transformer and the grounding resistor is specifically as follows: When the FPSO power system is a high voltage system, the high voltage switchboard of the high voltage system is electrically connected to the generator and the grounding transformer; When the FPSO power system is a marine medium voltage system, the medium voltage switchboard of the marine medium voltage system is electrically connected to the generator, the marine high voltage transformer and the grounding transformer; When the FPSO power system is a production medium voltage system, the neutral point of the production high voltage transformer of the production medium voltage system is electrically connected to the grounding resistor.

[0008] Furthermore, the high-voltage switchboard and the marine medium-voltage switchboard are both electrically connected to the grounding transformer via a connecting switch, and the connecting switch is electrically connected to a power management system.

[0009] Furthermore, the three phases of the source side of the grounding transformer are electrically connected to the power grid on the distribution board, the N phase of the grounding transformer is electrically connected to the ship ground, and the three phases of the secondary side of the grounding transformer are connected in series with each other and electrically connected to the resistor.

[0010] Furthermore, when the FPSO power system is a high voltage system, two grounding transformers are provided, and both grounding transformers are electrically connected to the tie switch and the switchboard; When the FPSO power system is a marine medium voltage system, two grounding transformers are provided, and both grounding transformers are electrically connected to the tie switch and the switchboard; When the FPSO power system is a production medium voltage system, two grounding resistors are provided, and one end of the two grounding resistors is electrically connected to the neutral point of the production high voltage transformer, and the other end of the two grounding resistors is electrically connected to the ship ground.

[0011] Furthermore, the method for determining the control mode between the distribution board and the grounding transformer includes: The FPSO power system is a high voltage system or a marine medium voltage system, and when the generator is running: When the tie switch is turned on, the grounding transformer corresponding to the energized switchboard is turned off, and the grounding transformer corresponding to the de-energized switchboard is turned on; When the tie switch is closed and the live switchboard is energized, one of the grounding transformers is closed and the other grounding transformer is opened; When the FPSO power system is a marine medium voltage system and the high voltage transformer is in operation: When the tie switch is turned on, the grounding transformer corresponding to the energized switchboard is turned off, and the grounding transformer corresponding to the de-energized switchboard is turned on; When the tie switch is closed and the live switchboard is energized, one of the grounding transformers is closed and the other grounding transformer is opened.

[0012] Compared with the prior art, the present invention has the following beneficial effects: Firstly, after the high-resistance grounding system is adopted in the present invention, when a short circuit occurs in the medium- and high-voltage power system, the excess charge accumulated during the short circuit can be discharged through the grounding transformer and the grounding resistor, thereby preventing the high oscillating overvoltage that may occur in the ground insulation system, thereby protecting the equipment of the power system from damage; Second, the present invention can significantly reduce the grounding short-circuit current and the impact of short-circuit faults on the power system by properly selecting the parameters of the grounding transformer or the grounding resistor, thereby improving the stability of the system. At the same time, by setting the parameters of the grounding transformer, it is ensured that the neutral point-to-ground current of the power system is greater than the grid capacitance current, thereby achieving a more reliable grounding effect without increasing too much system burden. Thirdly, the present invention automatically controls the connection switch state of the grounding transformer to ensure that the grounding transformer can be connected to or disconnected from the power grid in a timely manner according to actual needs under different FPSO operation modes, thereby reducing the possibility of human operation errors and improving the response speed of the system; Fourthly, the grounding resistor of the medium voltage production system of the present invention is directly connected to the N phase of the secondary side of the high voltage transformer, and only one transformer is connected to the grid at the same time, which is equivalent to introducing only one high-resistance grounding point at the same time, thereby simplifying the grounding control logic. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic flow chart of the grounding configuration method of the FPSO power system of the present invention. DETAILED DESCRIPTION

[0014] 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.

[0015] It should be noted that, in the description of the present invention, the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0016] Furthermore, it should be understood that for the sake of ease of description, the sizes of the various components shown in the drawings are not drawn according to actual proportions. For example, the thickness or width of certain layers may be exaggerated relative to other layers.

[0017] It should be noted that like reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined or described in one drawing, it will not require further detailed discussion and description in the description of the subsequent drawings.

[0018] refer to Figure 1 This embodiment provides a FPSO power system grounding configuration method, the FPSO power system grounding configuration method comprises the following steps: Step S1: Set the parameters of the grounding transformer and the grounding resistor according to the capacitance current of the grid of the FPSO power system. It is worth noting that when setting the parameters of the grounding transformer, it is necessary to ensure that the neutral point current to the ground of the FPSO power system is greater than the capacitance current of the grid of the FPSO power system. In other words, when the FPSO power system is a high-voltage system, the neutral point current to the ground of the FPSO power system is greater than the capacitance current of the high-voltage grid. When the FPSO power system is a marine medium-voltage system, in the FPSO power system, the neutral point current to the ground of the marine medium-voltage system is greater than the capacitance current of the marine medium-voltage grid. When the FPSO power system is a production medium-voltage system, in the FPSO power system, the neutral point current to the ground of the production medium-voltage system is greater than the capacitance current of the production medium-voltage grid.

[0019] Step S2: According to the type of the FPSO power system, the high-voltage switchboard and the marine medium-voltage switchboard in the FPSO power system are respectively connected to their corresponding grounding transformers, wherein the parameters of the grounding transformer are set according to the capacitance and current of the power grid. At the same time, the neutral point of the production high-voltage transformer is connected to the grounding resistor, wherein the parameters of the grounding resistor are set according to the capacitance and current of the power grid.

[0020] Further, the connection between the distribution board, high-voltage transformer, grounding transformer and grounding resistor is as follows: When the FPSO power system is a high-voltage system, the high-voltage distribution board of the high-voltage system is electrically connected to the generator and the grounding transformer. That is to say, in the high-voltage system of this embodiment, the high voltage is a 13.8KV system, and the total installed capacity is 5 13.8KV, 31.25MVA generators EG001-EG005. At the same time, the power grounding system adopts a neutral point non-effective grounding system. In the specific implementation process, the high-voltage distribution board of the high-voltage system of this embodiment is set as a 2-section EH001A / EH001B, and each section of the high-voltage distribution board is electrically connected to a grounding transformer ET001 / ET002. At the same time, one section of the high-voltage distribution board is electrically connected to 2 generators, and the other section of the high-voltage distribution board is electrically connected to 3 generators. It is worth noting that the neutral point of the generator is insulated from the ground, and is not connected to the hull of the ship using any grounding equipment.

[0021] Specifically, the grounding transformer adopts the Ynd0 wiring method, that is, the three phases of the source side of the grounding transformer are electrically connected to the power grid of the high-voltage distribution board, the N phase of the grounding transformer is electrically connected to the ship's earth, and the three phases of the secondary side of the grounding transformer are connected in series with each other and electrically connected to a 1.2Ω resistor. At the same time, the source side voltage of the grounding transformer set in the high-voltage system is set to 13.8KV, the secondary side voltage is set to 230V, the capacity is set to 28KVA, the zero-sequence resistance is set to 414Ω, and the rated grounding current is set to 50A, which can work continuously for 10S / 3.5A.

[0022] When the FPSO power system is a marine medium voltage system, the medium voltage distribution board of the marine medium voltage system is electrically connected to the generator, the marine high voltage transformer and the grounding transformer. That is to say, in the marine medium voltage system of this embodiment, the marine medium voltage is 6.6KV, and the power supply is 3 generators EG101-EG103 of 6.6KV and 3375KVA, and the power supply can also be 2 high voltage transformers TR101 / TR102 of 13.8 / 6.75KV and 20000KVA powered by the marine high voltage distribution board. It is worth noting that the generator and the marine high voltage transformer are not connected to the power grid at the same time, and a neutral point non-effective grounding system is adopted. In the specific implementation process, the medium voltage distribution board of the marine medium voltage system of this embodiment is set as a 2-section EH101A / EH101B, and a section of the high voltage distribution board is electrically connected to a grounding transformer ET001 / ET002 respectively. At the same time, one section of the medium-voltage distribution board is electrically connected to two generators and one high-voltage transformer, and the other section of the medium-voltage distribution board is electrically connected to one generator and one high-voltage transformer. And each section of the medium-voltage distribution board is electrically connected to a grounding transformer ET101 / ET102.

[0023] Specifically, the grounding transformer adopts the Ynd0 wiring method, that is, the three phases of the source side of the grounding transformer are electrically connected to the power grid of the high-voltage distribution board, the N phase of the grounding transformer is electrically connected to the ship's ground, and the three phases of the secondary side of the grounding transformer are connected in series and electrically connected to a 6.25Ω resistor. At the same time, the source side voltage of the grounding transformer set in the marine medium voltage system is set to 6.6KV, the secondary side voltage is set to 230V, the capacity is set to 7.6KVA, the zero-sequence resistance is set to 305Ω, and the rated grounding current is set to 20A, which can work continuously for 10S / 3.5A.

[0024] When the FPSO power system is a production medium voltage system, the medium voltage distribution board of the production medium voltage system is electrically connected to the production high voltage transformer. That is to say, in the production medium voltage system of this embodiment, the production medium voltage is 6.6KV, and the power supply is two 13.8 / 6.75KV, 18000KVA high voltage transformers TR201 / TR202. The production medium voltage system adopts a neutral point non-effective grounding system, and the two transformers do not work at the same time.

[0025] At the same time, the medium-voltage distribution board of the production medium-voltage system is a two-section EH201A / EH201B, one section of which is electrically connected to a production high-voltage transformer. At the same time, the neutral point N of the secondary side of the high-voltage transformer is electrically connected to the grounding resistor EJ201 / EJ202, with a resistance of 200Ω and a rated grounding current of 20A, which can operate continuously for 10S / 2A.

[0026] It is worth noting that, in this embodiment, when the FPSO power system is a marine / production low-voltage system, its power supply is a low-voltage transformer.

[0027] Step S3: According to the connection mode between the power distribution board, the high-voltage transformer and the grounding transformer determined in step S2, further determine the control mode between the power distribution board and the grounding transformer. Specifically: The high-voltage distribution board and the marine medium-voltage distribution board electrically connected to the grounding transformer can be electrically connected to the grounding transformer through a connecting switch, and the connecting switch is electrically connected to the power management system, that is, the connecting switch can be directly managed and controlled by the power management system.

[0028] It is worth noting that since the grounding resistance of the production medium voltage system is directly electrically connected to the N phases of the secondary side of the high-voltage transformer, and only one transformer is connected to the grid at the same time, that is to say, it is equivalent to introducing only one high-resistance grounding point into the production medium voltage system at the same time, so the grounding resistance does not need to be controlled separately.

[0029] In this embodiment, the method for determining the control mode between the distribution board and the grounding transformer is specifically as follows: When the FPSO power system is a high voltage system or a marine medium voltage system and the generator is running: When the contact switch is turned on, the grounding transformer corresponding to the energized distribution board is turned off, and the grounding transformer corresponding to the de-energized distribution board is turned on.

[0030] When the tie switch is closed and the live switchboard is energized, one of the grounding transformers is closed and the other grounding transformer is opened.

[0031] In the specific implementation process, the control logic between the 13.8KV high-voltage distribution and grounding transformers is shown in the following table:

[0032] In the specific implementation process, the control logic between the 6.6KV marine medium voltage distribution and grounding transformer is shown in the following table, and the power is supplied by the high voltage transformer.

[0033]

[0034] When the FPSO power system is a production medium voltage system and the high voltage transformer is in operation: When the tie switch is turned on, the grounding transformer corresponding to the energized switchboard is turned off, and the grounding transformer corresponding to the de-energized switchboard is turned on; When the tie switch is closed and the live switchboard is energized, one of the grounding transformers is closed and the other grounding transformer is opened.

[0035] In the specific implementation process, the control logic between the 13.8KV high-voltage distribution and grounding transformer is shown in the following table, and the power is supplied by the generator.

[0036]

[0037] Step S4: Determine the grounding method according to the type of FPSO power system, specifically: When the FPSO power system is a high voltage system, the high voltage switchboard is electrically connected to the grounding transformer.

[0038] When the FPSO power system is a marine medium voltage system, the medium voltage switchboard is electrically connected to the grounding transformer.

[0039] When the FPSO power system is a production medium voltage system, the neutral point of the production high voltage transformer is electrically connected to the grounding resistor.

[0040] When the FPSO power system is a marine / production low voltage system, the low voltage switchboard is electrically connected to the power grounding system which is insulated from the ground.

[0041] That is to say, when a short circuit occurs in a medium- and high-voltage power system, the FPSO power system grounding configuration method of this embodiment can leak the excess charge accumulated during the short circuit through the grounding transformer or grounding resistor. Compared with the ground insulation system, the high-resistance grounding system can prevent the generation of very high oscillating overvoltage. Compared with the neutral point direct grounding system or the low-resistance grounding system, the grounding short-circuit current is reduced.

[0042] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is limited by the attached embodiments and their equivalents.

Claims

1. A method for grounding configuration of an FPSO power system, characterized in that: The grounding configuration method includes: The parameters of the grounding transformer and grounding resistance are set according to the grid capacitance current of the FPSO power system; According to the type of the FPSO power system, the high-voltage switchboard and the marine medium-voltage switchboard in the FPSO power system are connected to the grounding transformer, and the neutral point of the production high-voltage transformer is connected to the grounding resistor; Determine the control mode between the power distribution board and the grounding transformer according to the connection mode between the power distribution board, the high voltage transformer and the grounding transformer; According to the type of FPSO power system, the grounding method is determined as follows: When the FPSO power system is a high voltage system, the high voltage switchboard is electrically connected to the grounding transformer; When the FPSO power system is a marine medium voltage system, the marine medium voltage switchboard is electrically connected to the grounding transformer; When the FPSO power system is a production medium voltage system, the neutral point of the production high voltage transformer is electrically connected to the grounding resistor; When the FPSO power system is a marine / production low voltage system, the low voltage switchboard is electrically connected to the power grounding system which is insulated from the ground.

2. A FPSO power system grounding configuration method according to claim 1, characterized in that: The neutral point-to-ground current of the FPSO power system is greater than the grid capacitance current of the FPSO power system.

3. A FPSO power system grounding configuration method according to claim 1, characterized in that: The connection method between the high-voltage switchboard, the marine medium-voltage switchboard, the marine high-voltage transformer, the grounding transformer, and the grounding resistor is specifically as follows: When the FPSO power system is a high voltage system, the high voltage switchboard of the high voltage system is electrically connected to the generator and the grounding transformer; When the FPSO power system is a marine medium voltage system, the medium voltage switchboard of the marine medium voltage system is electrically connected to the generator, the marine high voltage transformer and the grounding transformer; When the FPSO power system is a production medium voltage system, the neutral point of the production high voltage transformer of the production medium voltage system is electrically connected to the grounding resistor.

4. A FPSO power system grounding configuration method according to claim 3, characterized in that: The high-voltage switchboard and the marine medium-voltage switchboard are both electrically connected to the grounding transformer via a connecting switch, and the connecting switch is electrically connected to the power management system.

5. A FPSO power system grounding configuration method according to claim 3, characterized in that: The three phases of the source side of the grounding transformer are electrically connected to the power grid on the distribution board, the N phase of the grounding transformer is electrically connected to the ship ground, and the three phases of the secondary side of the grounding transformer are connected in series and electrically connected to the resistor.

6. A FPSO power system grounding configuration method according to claim 4, characterized in that: When the FPSO power system is a high voltage system, two grounding transformers are provided, and both grounding transformers are electrically connected to the tie switch and the switchboard; When the FPSO power system is a marine medium voltage system, two grounding transformers are provided, and both grounding transformers are electrically connected to the tie switch and the switchboard; When the FPSO power system is a production medium voltage system, two grounding resistors are provided, and one end of the two grounding resistors is electrically connected to the neutral point of the production high voltage transformer, and the other end of the two grounding resistors is electrically connected to the ship ground.

7. A FPSO power system grounding configuration method according to claim 1 or 4, characterized in that: The method for determining the control mode between the distribution board and the grounding transformer includes: The FPSO power system is a high voltage system or a marine medium voltage system, and when the generator is running: When the tie switch is turned on, the grounding transformer corresponding to the energized switchboard is turned off, and the grounding transformer corresponding to the de-energized switchboard is turned on; When the tie switch is closed and the live switchboard is energized, one of the grounding transformers is closed and the other grounding transformer is opened; When the FPSO power system is a marine medium voltage system and the high voltage transformer is in operation: When the tie switch is turned on, the grounding transformer corresponding to the energized switchboard is turned off, and the grounding transformer corresponding to the de-energized switchboard is turned on; When the tie switch is closed and the live switchboard is energized, one of the grounding transformers is closed and the other grounding transformer is opened.

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