JP2565570B2 - Ground fault current suppression method and device in three-phase water resistor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to suppression of ground fault current in a three-phase water resistor used for measurement test and inspection of output characteristics of various power supply devices including generators and inverters. Regarding the device.

[Prior Art] The load device system of Japanese Patent No. 1462423 of the present applicant minimizes abnormal voltage boosting by directly grounding the neutral point of three-phase power in order to ensure the safety of the operator.
It is a structure that ensures the operation of the protective device.

Therefore, when the three-phase voltage is unbalanced and the current of each phase of the three-phase water resistor is unbalanced, this current flows as a ground fault current.

That is, as shown in FIG. 7, the three-phase water resistor A includes a bottomed cylindrical base electrode 1a, 1b, 1c for storing a predetermined amount of electrode water W circulated and supplied therein, and the base electrode 1a, 1b, 1c bottom
2a, 2b, 2c The drainage holes 3a, 3b, 3c are opened at appropriate places, and the insulating supports 4a, 4b, 4c vertically attached to the center of the drainage holes 3a, 3b, 3c are erected vertically. Cable La, Lb, Lc
And a cylindrical main electrode 5a, 5b, 5c for connecting the main electrode 5a, 5c
b, 5c, and insulating sheath cylinders 7a, 7b, 7c that open the discharge ports 6a, 6b, 6c of the circulating supply water W that are cooled at the top,
The base electrodes 1a, 1b, 1c are connected to the ground G via a neutral point 0 grounding cable L0 which is concentratedly connected to each other by cables L1, L2, L3. Therefore, it becomes a Y-connected resistor.

The principle of generation of ground fault current in this neutral point grounding method is
It can be verified as an asymmetrical Y-shaped load, and when an asymmetrical Y-shaped electromotive force is added to this, the power supply unit shown in FIG.
PS electromotive force Ea, Eb, Ec and load impedance Za, Zb, Zc
Are all asymmetric. The impedance of the neutral line L0
It is assumed that Zn is the impedance of the lead wires La, Lb, Lc of each phase and the PS coil of the power supply device are included in Za, Zb, Zc.
Since the entire circuit is asymmetric, the neutral point 0 of the load has a certain potential with respect to the neutral point 0'of the power supply PS. Let this be Vn. In that case, when all the impedances are expressed in the form of admittance, the following relationship is established according to Kirchhoff's law.

Ia = Ya (Ea-Vn) Ib = Yb (Eb-Vn) (1) Ic = Yc (Ec-Vn) In = -YnVn where Ya = 1 / Za, Yb = 1 / Zb Yc = 1 / Zc, Yn = 1 / Zn However, because Ia + Ib + Ic + In = 0, Vn (Ya + Yb + Yc + Yn) = YaEa + YbEb + YcEc These are general formulas for calculating the ground fault current In to the neutral line L0 of the unbalanced current of the three-phase water resistor A.

On the other hand, in this type of conventional three-phase water resistor, its grounding method and insulation method from the ground are unclear, and it is dangerous to know where abnormal potential occurs and where ground fault current flows. Met.

[Problems to be Solved by the Invention] Whether the load device system of the present applicant or the conventional general three-phase water resistor is connected as a load resistance to a transmission line of an electric power company, an unbalanced current of each phase is generated. Flows to the ground through the part that is not insulated from the ground.

This unbalanced current is detected as a ground fault current in the power transmission system of the electric power company, is determined to be a failure, and this system is disconnected, causing a regional power outage.

For that reason, if a protective relay is inserted to prevent a ground fault current, the protective relay is frequently disconnected each time an abnormal current flows.As a result, the test measurement that requires a constant continuous time must be redone each time, which is efficient. It could not be inserted to make the measurement.

In view of the disadvantage of the neutral point grounding method by the conventional Y connection of the three-phase water resistor, the present invention provides a three-phase water resistor that is effective as a non-grounding method that does not allow a three-phase unbalanced current to flow to the ground. It is intended to provide a ground fault current suppressing device.

[Means for Solving the Problems] In order to solve the above problems, according to the present invention, three bottomed cylindrical bases in which bottoms are penetrated at equal intervals and are connected to a top plate of a water collector mounted on a receiving stand are formed. An insulating support is pierced through the center of each bottom end of the electrode, the water collector top plate, and the pedestal, and the protruding upper end of the electrode connecting rod that vertically penetrates the insulating support is provided on the insulating support. While connecting and fixing the bottom end of the main electrode to be erected and connecting the power cable of the power supply device to the lower end of the outside, cover each insulating sheath cylinder to adjust the exposed length of each main electrode, and attach the lower part to the base electrode. On the other hand, three branch pipes that are hung from the bottom plate of the water diverter at equal intervals corresponding to the respective main electrodes are inserted through the insulating sheath cylinders and the respective lower ends are released. In a three-phase water resistor having outlets directly above the main electrode, the pedestal and the A water vessel is installed and insulated from the ground through an insulator, and a discharge side end of an electrode water cooling circulation conduit for supplying and discharging a predetermined amount to keep the electrode water temperature and water amount in each of the base electrodes constant. The outlet of the water collector and the end of the water supply side and the water supply port of the water divider are insulated and connected by insulating hoses, and the side circumference of the three-phase water resistor is transparently transparently visible. The three-phase water resistor is surrounded by a plate to insulate and isolate the upper and lower ends and the side circumference of the three-phase water resistor from the insulating support, and the electrode water cooling circuit and the three-phase water resistor are insulated and connected. ,
This is achieved by adopting an abnormal component.

[Operation] The present invention takes the above-mentioned means and installs the three-phase water resistor in the three-phase water resistor so that the abnormal current generated by insulating the upper, lower, front, rear, left and right sides from the ground current does not flow to the ground. The surrounding side of the containment is transparent and visible, and is surrounded by a transparent insulating plate to ensure safety so that people and animals cannot be inadvertently touched.

[Embodiment] An embodiment of the device of the present invention will be described with reference to FIGS.

The three-phase water resistor B applied to the present invention is a bottomed base electrode 11a, 11b in which bottoms of the top plate 10 of the water collector 9 mounted on the pedestal 8 are connected at equal intervals in the longitudinal and lateral directions. , 11c drain holes 12a, 1
Water collector 9 and the center of each bottom end 13a, 13b, 13c penetrating 2b, 12c
Over the bottom plate 14 and the pedestal 8 upper plate 15, insulating supports 16a, 16 are provided.
b, 16c is penetrated, and the insulating support members 16a, 16b, 16c are protruded upper ends of the electrode connecting rods 17a, 17b, 17c, and the insulating support members 16a, 16b, 16c are circular recessed seat portions 18a, 18b, 18c at the upper end. Main electrodes 19a, 19b, 1 installed inside
While connecting and fixing the bottom ends 20a, 20b, 20c of 9c, while connecting the power cables La, Lb, Lc of the power supply device PS to the outside lower end, cover to adjust the exposed length of each main electrode 19a, 19b, 19c Each insulating sheath cylinder 21a, 21b, 21c is connected to each base electrode 19a, 19b, 1
The lower part is inserted into 9c and suspended vertically by a connecting rod 22 so that it can be lifted and lowered integrally.On the other hand, branch ports corresponding to the main electrodes 19a, 19b, 19c are provided at equal intervals in the longitudinal and lateral directions of the bottom plate 24 of the water diverter 23. Branch pipes 26a, 26b, 26c hanging down to 25a, 25b, 25c are passed through the respective insulating sheath cylinders 21a, 21b, 21c and the respective lower end discharge ports 27a, 27b, 27c are directly above the upper ends of the main electrodes 19a, 19b, 19c. I will face you.

In the ground fault current suppressor of the present invention, both ends of the lower end of the pedestal 8 are supported and erected on the floor surface or the cargo bed G1 via the insulators 28a, 28b, while the upper ends of the water divider 23 are insulated by the insulators 29a, 29b. Is erected and supported on the ceiling surface G2 via the base electrode 11a, 11b, 11
Insulation hose 33 is used to connect the drainage side end 31a of the electrode water cooling circulation line 30 for supplying and discharging a predetermined amount of the electrode water W in c to a constant amount and the discharge port 32 of the water collector 9 with an insulating hose 33. Side edge 31b and water divider 2
The three water supply ports 34 are connected to each other by insulating hoses 35, and the entire side circumference of the three insertion resistors A is surrounded and isolated by a transparent plastic insulating plate 36.

 In the figure, 37, 38, 39 and 40 are fastening rings.

The water resistor electrode water circulation processing system device C connected to the three-phase water resistor B has a flow of, for example, a regular 1 kg / cm ^{2 in} the middle of the discharge side of the electrode water cooling circulation line 30 near the discharge port 42 of the electrode water pump 41. Insert the switch type flow meter 43 and the safety circuit breaker 44 in the three-phase power cables La, Lb, Lc
Detects that the amount of drainage from the outlet 42 of the electrode water circulation pump 41 has fallen below a preset value, it issues a current interruption command signal s to disconnect the safety circuit breaker 44 and the current from the power supply device PS is three-phase. While there is a momentary disconnection so that it will not be sent to the water resistor B, sprays 45a, 45b,
A plurality of radiators 47a, 47b, 47c with an air-water cooling hood, which are provided with 45c and fans 46a, 46b, 46c, are provided in a plurality of stages (3 in the case of the present embodiment).
(Step) The cooling capacity of the electrode water W is enhanced by interposing in series.

In the figure, 48 is a safety circuit breaker, 49 is a flushing return line 50 and pure water filling line 51, and various processes bypass-connected to the electrode water cooling circulation line 30 and various processes including devices such as a purifier and a filter. It is a system.

 The safety circuit breaker 44 may also be used as the safety circuit breaker 48.

The specification of the present embodiment presents such a concrete embodiment, and the idea of the idea leading to this is as follows. In FIG. 8, the unbalanced current is the unbalanced of the line voltages Ea, Eb, Ec on the transmission side, Since it cannot be prevented due to the connection status of other loads to each group and the imbalance of each phase of the three-phase water resistor B, the above (1)
It is to devise so that In = −YnVn = 0 from the formula.

Since the voltage Vn of the neutral line L0 is generated due to the imbalance, it cannot be prevented, but the admittance Yn of the neutral line L0 approaches 0. That is, the impedance Zn of the neutral line L0 may be increased.
In the method, if the neutral point 0 of the base electrodes 11a, 11b, 11c is insulated from the ground G, the current In = 0 flowing in the neutral line L0 can be approached.

However, since the three-phase water resistor B uses the conductive water W, if a conductive metal pipe is used for the electrode water cooling circulation line 30, a current flows through this. In order to prevent this, the insulation pipes 33, 3 are provided at the connection end of the electrode water cooling circulation line 30 with the three-phase water resistor B.
By using 5, it is possible to suppress the current to the amount that flows in the electrode water W in both. Therefore insulating pipes 33,3
5 also prevents the adverse effects of the leakage current from the three-phase water resistor B including the unbalanced ground fault current.

On the other hand, if the impedance Zn (1 / Yn) of the neutral wire L0 is increased, the unbalanced voltage will be generated at the neutral point 0 potential of the three-phase water resistor B, and it becomes dangerous. Insulation plate 36 to prevent people and animals from touching 11a, 11b, 11c
The side circumference is isolated by.

Therefore, when trying to calculate the unbalanced current that flows at the neutral point 0, if the voltage is 6,600V and the three-phase 1,000KW unbalanced rate is 5% as the reference value, the line voltage is 6,600V when balanced. Phase voltage Phase current at equilibrium 87.58A Phase resistance at equilibrium Za = 43.56Ω… Main resistance Conductivity of water δ = 100μs / cm.

Assuming imbalance, Za = -5%, that is, Ya = + 5.
%.

Next, as shown in FIG. 5, the electrode water resistance value R1 in the water supply side conduit of the electrode water cooling circulation conduit 30 is 6 cm for the conduit inner diameter and 1 for the length l.
If you use m one, However, S1 is the cross-sectional area in the conduit, and δ is the conductivity of water. The electrode water resistance value R2 in the drain side pipeline is 8 cm for the pipeline inner diameter and l
If you use a 1m The parallel resistance value R0 of the electrode water in the pipeline on the water supply side and the drainage side is If points X and Y in Fig. 5 are connected to clarify the analysis of the resistance value, the combined value becomes R0 and the impedance of the neutral line L0 becomes Zn = 12.7 × 10 ³ Ω using the equation (1). .

Therefore, each voltage Ea, Eb, Ec and the main resistance value (unbalance ratio 5%) and Zn1 = 0 (direct ground), Zn2 = 12.7 ×
Substitute 10 ³ Ω and try to compare.

Finally, when Zn1 = 0 (neutral point grounding method) Vn1 = 0, In1 = 85.7 × 0.05 = 4.285A Zn2 = 12.7 × 10 ³ Ω (inventive non-grounding method) When comparing the two, the ground fault current flowing to the ground G through the electrode water W in the electrode water cooling circulation line 30 is In2 / In1 = 4.92 × 10 ^-3 /4.258 = 1.148 × 10 ^-3 , which is 1/1000. Can be suppressed to

On the other hand, the neutral point 0 potential is 62.5 V at 5% unbalance, but as shown in FIG. 6, the three-phase conductors La, Lb, Lc and the neutral point 0 are
Three-phase water resistor with base electrodes 11a, 11b, 11c and main electrodes 19a, 19b, 19c to prevent electric shock due to abnormal voltage at neutral point 0 during short circuit (arc α generation ... flashover (OV)) B is insulated and supported by the insulators 28a, 28b, 29a, 29b on the floor surface or the loading platform G1 and the ceiling G2, and the side circumference is insulated by an insulating plate 3
Surround it with 6 and make it an insulating structure that is not touched by humans or animals.

In short, the device of the present invention isolates and insulates the upper and lower ends and the side circumference of the three-phase water resistor B from each other, and keeps the electrode water W temperature and amount in each base electrode 11a, 11b, 11c constant. An electrode water cooling circulation line 30 for supplying and discharging a fixed amount and a three-phase water resistor B are connected in an insulated manner.

[Effects of the Invention] Thus, the present invention completely confines the unbalanced current in the three-phase water resistor by insulating the abnormal current generated from the three-phase water resistor itself except through the electrode water in the electrode water cooling circulation line. Therefore, the cause of the artificial power outage caused by the electric power company, which was previously caused by the ground fault current flowing to the earth, is eliminated, and it does not bother local residents and the electric shock accident when people and animals touch the three-phase water resistor during operation. The side circumference is surrounded by an insulating plate so as to prevent the occurrence of noise and isolated from the outside world.

[Brief description of drawings]

FIG. 1 is a schematic front view of a partially broken three-phase water resistor provided with the device of the present invention, FIG. 2 is a plan view of the same as above with the water divider and the branch pipe removed, and FIG. 3 is a plane of the water divider. Fig. 4 is a connection system diagram of a three-phase water resistor and a water resistor electrode water circulation treatment system device to which the device of the present invention is applied, and Fig. 5 is an electrode main resistance and electrode water cooling circulation of the three-phase water resistor. Connection diagram of electrode water resistance in pipeline, FIG. 6 is an explanatory diagram of short-circuit arc generation at a neutral point of a three-phase conductor of a three-phase water resistor provided with the device of the present invention, and FIGS. 7 to 8 are three-phase. It is explanatory drawing of the conventional neutral point grounding system in a water resistor, and its principle explanatory drawing. A, B …… Three-phase water resistor, C …… Water resistor Electrode water circulation processing system device La, Lb, Lc …… Power cable or conductor L1, L2, L3 …… Cable or conductor 1a, 1b, 1c, 11a , 11b, 11c ...... Base electrode L0 ...... Ground cable or neutral wire 3a, 3b, 3c, 12a, 12b, 12c ...... Drainage hole 4a, 4b, 4c, 16a, 16b, 16c ...... Insulation support 5a, 5b, 5c, 19a, 19b, 19c …… Main electrode 6a, 6b, 6c, 27a, 27b, 27c …… Emission port 7a, 7b, 7c, 21a, 21b, 21c …… Insulation sheath 0,0 ′ …… Neutral point, G ... earth G1 ... floor or cargo bed, G2 ... ceiling PS ... power supply, 8 ... cradle 9 ... water collector, 10 ... top plate 13a, 13b, 13c, 20a , 20b, 20c ...... Bottom end 14, 24 ...... Bottom plate 17a, 17b, 17c ...... Electrode connecting rod 22 ...... Connection rod, 23 ...... Water divider 26a, 26b, 26c …… Branch pipe 28a, 28b, 29a , 29b …… Insulator 30 …… Electrode water cooling circulation line 31a …… Drain side end, 32 …… Drain port 33,35 …… Insulation hose, 34 …… Water inlet 36 …… Insulation plate

Claims (1)

(57) [Claims] 1. The center of each bottom end of three bottomed cylindrical base electrodes which are connected to the top plate of a water collector mounted on a pedestal at equal intervals, and the bottom plate of the water collector. The insulation supports are pierced through the pedestal, and the bottom ends of the main electrodes that are placed on the insulation supports are connected and fixed to the protruding upper ends of the electrode connecting rods that vertically penetrate the insulation supports. While connecting the power cable of the power supply device to the lower end, each insulating sheath that covers to adjust the exposed length of each main electrode is hung so that it can be integrally moved up and down by inserting the lower part into each base electrode. Three branch pipes hanging down on the bottom plate of the water distributor at equal intervals corresponding to the respective main electrodes are respectively passed through the insulating sheath cylinders, and the respective lower end discharge ports are made to face directly above the upper end of the main electrode. In the three-phase water resistor that performs the measurement test and inspection of the output characteristics of the power supply device, And a pipe of a water resistor electrode water circulation treatment system device for insulatingly supporting and erecting the ground and the ceiling via insulators, respectively, and supplying and discharging a predetermined amount to keep the electrode water temperature and water amount in each of the base electrodes constant. The water resistor and the water resistor electrode water circulation treatment system are formed by connecting the drain side end of the channel and the outlet of the water collector and the water supply side end and the water inlet of the water divider with insulating hoses, respectively. A ground fault current suppressing device in a three-phase water resistor, which is insulated from the device, and further is surrounded by a transparent insulating plate so that the front, rear, left and right four sides of the three-phase water resistor are transparently visible.