JPS6240016A - Inspection system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inspection system for an input device for a ratio differential relay that protects the busbars of a power system.

[Conventional technology]

A conventional inspection method of this type is disclosed in Japanese Patent Publication No. 52-12878. FIG. 2 shows a conventional example when applied to a current ratio differential relay.

In the figure, (1) is the bus line, (2-1) to (2-n
) CT (current transformer), (8-1) to (8-n) are input devices, (4) is a quadrangle with a gear joint, (hereinafter referred to as input quadrangle) (4-1) is an input transformer (4 ), (4-2) is the 8th coil of the input quadrangle (4)/
L/, (4-8) is the inspection coil l of the input quadrangle (4),
<8) is a rectifier circuit, (6) is a tap (hereinafter referred to as a tap) that changes the primary coil turn of the input transformer (4), (14) is a ratio differential relay (hereinafter referred to as a main relay), (9-1) to (9-n) are inspection command contacts which are closed during inspection (hereinafter referred to as inspection contacts) 1 Next, the operation shown in FIG. 2 will be explained. Main relay 04i
, t bus (1) O CT internal failure (2-1) ~
(2-rl) and has the purpose of operating the circuit breaker of each line connected to the bus (1).
) to (2-n) to input devices (a-1) to
(8-n), and its input devices (8-1) to (
The operation is determined based on the output of 8-n). Operation amount cover OT of main relay α→ (2-1) to (2-n)
The secondary current is received by the input quadrature transformer (4) of the input device (8-1") to (8-n), and the input quadrature transformer secondary coil (4)
-1) is combined by vector)/of all lines. (This is called a differential voltage.) When a fault occurs inside the bus bar, a voltage proportional to the fault current is generated, and when an external fault occurs, the differential voltage becomes zero. On the other hand, the suppression input of the above-mentioned raw wire α fathom is the 8th order carp /l/(4-2) of the input transformer (4).
The output is full-wave rectified by the rectifier circuit (8), and the suppressing input is proportional to the OT secondary current of each line.

In order to check the operating state of the bus protection relay device configured as described above, input devices (8-1) to (
The characteristics are confirmed by applying a predetermined input via the input terminal (ill-n).

Next, the method of the inspection operation will be explained. Enter Kadrance (4)
) secondary coil (4-1) or 8th coil/v (4-2)
In order to check for disconnections or short circuits, etc., and to check the operating characteristics of the main relay 04, the inspection contacts (9-1) to (9-n) are sequentially closed via an inspection power transformer (not shown). ,
The operation of the main relay Q4 is confirmed by applying a simulated input to the input transformer inspection coil /l/(4-8). In addition, in order to inspect the suppression output circuit consisting of the 8th order coil/L' (4-2) of the input cadence (4) and the rectifier circuit (8), and to inspect the ratio characteristics of the main relay, for example, the input device (8 −
1) Inspection coil /L/(4-8) has electrician 1 Inspection coil 1v (4-8) of other input device (]-n) has electrician 1
By applying I, which is the opposite polarity to that of , the operation amount of the main relay is I, -
A simulated input proportional to I, , and I is applied as the suppression amount, but in order to perform highly accurate inspection, it is necessary to apply a large inspection input to the extent that the influence of the load current can be ignored. The tap (6) is for compensating the CT ratio when the OT ratio of each line is different, and is configured to change the primary coil turn of the input transformer (4).
Even if the tap is changed, the ratio of the secondary coil turn to the tertiary coil turn does not change.Therefore, even if the tap is changed and the inspection input is applied to the inspection coil 1 (4-8), the secondary coil A/
The inspection output derived in (4-1) has the advantage of not changing.

[Problems to be solved by the invention] Since the conventional inspection device for the bus protection relay device is configured as described above, the tap (6) of the input transformer (4) is
When installed on the next coil (4-1) side, inspection input can be performed by changing the tap when performing an inflow-outflow characteristic (ratio characteristic) inspection using two input devices (or one is a power supply for inspection only). Due to this change, normal inspection cannot be carried out. In addition, the differential output is always zero even if there is a tidal current, but since the tidal current is always applied to the suppression output, it is superimposed on the inspection input and causes errors, making it impossible to perform high-precision inspection. .

Therefore, at the time of inspection, it is necessary to perform a large input inspection to the extent that changes in power flow can be ignored in order to avoid erroneous judgments, which has the disadvantage of increasing the capacity of the inspection power supply.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and the input devices (S-1) to (8-n)
The tap (6) of the input drift lance (4) can also be used when installed on the secondary coil (4-1) side, and also enables high-precision inspection of the input device without being affected by tidal currents. The purpose is to provide a method.

[Failure to solve the problem]

The inspection method for the input device for a ratio differential relay according to the present invention includes a suppression output level detector and a differential output level detector dedicated for inspection, a circuit that applies a simulated input to the input quadrature inspection coil of each input device, and an input device. A reference output generation circuit is provided to compare whether the differential output value generated by the device is within a specified value, and a switch is provided to set the reference output according to the tap of each input device.

[Effect]

The inspection method of the input device in this invention is to apply a simulated input to the input transformer inspection coil of the input device, compare the differential output generated on the secondary coil side with the reference output, and if the output difference is more than a specified value, the difference is detected. The dynamic output level detector operates and detects an abnormality. At the same time, a suppression output level detector is used to confirm that the suppression output repetition μ is greater than a specified value.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to FIG. 1. In FIG. 1, the same or corresponding parts as in FIG. 2 are indicated by the same reference numerals (5-1) to (5-4).

(i8-D~(lfll-4) is a resistance, (6) is (6-
1) to (6-n) switching switches or taps (hereinafter referred to as switching devices), (7) is a transformer, αO is an inspection power supply,
αυ is the inspection power transformer (hereinafter referred to as transformer), (2
) is the standard output transformer for inspection (hereinafter referred to as transformer),
θG is a suppression output level detector (hereinafter referred to as suppression detector)
, 0Q are differential output level detectors (hereinafter referred to as differential detectors).

Next, the operation of this invention will be explained. Input device (il
l-1"l to C3-n) all have the same configuration, and the current transformers (2
-1) to (2-n) are received by the input transformer (4) and the output voltage of the secondary coil (4-1) is controlled by the resistors (5-1) to (2-n).
5-4) to divide the pressure, and select the partial pressure ratio with the switch (6).

The output of this switch (6) is set as a differential output, and the output of this switch (6) is received by a transformer (7), and the output is full-wave rectified by a rectifier circuit (8), and the output is set as a suppression output. The differential outputs of the input devices (S-1) to (8-n) configured as above are all connected in series, and this is used as the operating amount of the main relay Q41 to suppress the input devices (8-1) to (8-n). This is to check the input device of the ratio differential relay α-X, in which all outputs are connected in parallel and this is used as the suppression amount of the main relay Q4). Input device (
11), close the contact (9-1) and connect the input transformer (4) inspection coil z+/(4-
Apply inspection input to J) and transformer (2), and if the input device (8-1) is normal, the suppression detector α frame will operate and the differential detector (L) will not operate. The judgment is A, where the suppression detector (G) operates and the differential detector αQ does not operate.
The ND condition may be used. The suppression detector (to) detects the suppression output level proportional to the superimposed value of the inspection input and the constant current, so the inspection accuracy is as bad as the conventional one, but the transformer (7)
) and rectifier circuit (8) and to check that the power supply application circuit is normal. In other words, although the accuracy check is performed using the differential detector 0Q, the system determines that the check is normal when the differential detector αQ is not operating.
For example, transformer (b), (6) or contact (9-t) to (
Even if 9-n') is abnormal and no inspection input is applied, the differential detector αG may incorrectly judge that the inspection is normal, so the suppression inspection device (to) is used to confirm that the inspection input is applied. It is. The differential detector αQ has input devices (a-1) to (
It detects the difference voltage between the differential output VD of a-n) and the reference voltage ■s generated by the transformer @, but the differential output is not always affected by the tidal current (due to the differential principle, the tidal current is always present). (The differential voltage becomes zero), so extremely sensitive detection can be achieved.

In other words, when inspecting the input device (8-1), transformer a
The simulated input generated from η is input to the inspection coil (4-8) of the input quadrature transformer (4) of the input device (8-1') and the transformer (
2), the input Katlanne (4) and resistors (5-1) to (5-4), transformer @ and resistor (1)
8-1) to (1i11-4), the differential voltage VD generated from the input device (a-1)
and the transformer @ Above all, the generated reference voltage vs is the same value, and if the circuit is normal, the error voltage of VD-vs will be an extremely small value, so even if the differential detector α13 is set to high sensitivity, there will be no erroneous judgment. do not have. In addition, the switch (6-1) ~ (6-
n) is a switch (6) for input devices (8-1) to (8-n)
The taps of each input device (a-1) to (8-n) can be changed freely. Although Fig. 1 shows only one phase, the main relay Q4, suppression detector (to), differential detector αQ, and input devices (8-1) to (8-n) are for three phases. Contacts (9-1) to (9-n), switch (6-1) to (6
-n)) run 7Ql), u resistance (18-1)~
(18-4) can be applied to one phase, and the input to the inspection coil (4-8) can be applied in series for three phases, and the reference human power ■s to the differential detector QQ can be applied in parallel to each phase. Good. In the above embodiment, the case of protection for a single bus bar was shown, but an example of application to a double bus bar is shown in FIG. In the figure, α force, (
(to) is a disconnector G, and (17a) and (18a) are each a disconnector G.
(Hb), (xsb) are auxiliary relay contacts (hereinafter referred to as contacts) that close when each disconnector αη, (to) is disconnected (hereinafter referred to as contacts). , and the same reference numerals as in FIG. 1 indicate the same or equivalent parts as in FIG. 1. In case of double busbar protection, current transformers (2-1) to (2-
It is necessary to switch the output of the input devices (8-1) to (8-n) according to the state of the secondary current of the disconnector αη, (to), and the main relay 04 also connects to the bus (1-1). and (1-2) are required respectively. The output of the input quadrangle (4) is the disconnector αη.

Depending on the state of (g), it is switched by contacts (17a), (17b) or contacts (18a), (18b), but the inspection input application circuit is the same as in FIG. 1, although not shown. When inspecting the input device (8-1), contact (9-1)
is closed and a simulated input is applied to the inspection coil /l/ (4-8), and the output derived from the contact (17a) side or the contact (18a) side is suppressed by the detector (15-1) and differential detection. Vessel (16-
t) or suppression detector (15-2), differential detector (16-
2), and the detection method is the same as in the case of FIG. Judgment is made by the detectors (15-1) and (16-1) and the detector (15-2).

(16-2) is ORed. In other words, the output of the input device (a-1) to C3-n) is the contact point (17aM
17b) or (18a) and (18b), the signal is output to the detector (15-1) and (16-1) or the detector (15-2).

(16-2) It is uncertain whether it will be output to the side, but if either or both of the disconnectors αη and (g) are turned on, when the circuit is normal, the detectors (15-t) and (16
-t) side or the detector Q5-2), (16-2) side must detect it. As described above, even with double bus protection, by combining the conditions of the disconnector αη (to), the input device (1
High precision inspections of 3-1) to (8-n) can be performed. Although the explanation so far has not mentioned the inspection of the main relay It may be applied to the differential input terminal and the suppression input terminal, and since the VA consumption of the main relay is generally extremely small, the inspection power supply capacity becomes small.

〔Effect of the invention〕

As described above, according to the present invention, the input device (8-1)
~C3-n) For the purpose of downsizing and improving the reliability of the OT secondary circuit, when the primary coil p tap of the input transformer (4) is abolished and a tap switching circuit is installed on the secondary coil/L' side. In addition, most of the input device 4 components and circuits can be inspected with high-precision inspection that is not affected by tidal currents, and it also has the effect of reducing the capacity of the inspection power supply, reducing the cost of the entire device. This also has the effect of improving the reliability of the device.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an inspection method for an input device for a ratio differential relay according to an embodiment of the present invention, FIG. 2 is a circuit diagram showing a conventional inspection method, and FIG. 3 is another embodiment of the present invention. FIG. 2 is a circuit diagram illustrating the application side to double bus bar protection. In the drawings, the same reference numerals indicate the same or equivalent parts. (1), (1-1), (x-2)... bus line,
(2-1'l~(2-n)...Current transformer, (8-1)~
(8-n)...Input device, (4)...Gap transformer, (5-1) to (5-4), (18-1)-
(18-4)...Resistance, (6), (6-1) ~ (6
-n)...Switcher, (7)...Transformer, (8)
... Rectifier circuit, (9-1) to (9-n) - contact, G
O-...Inspection power supply, αυ...Inspection power transformer, @-
...Transformer with gear and knob, α fathom...Ratio differential relay, C1!9, (15-1). (15-2)...Suppression level detector, αL (16-
1), (16-2)...Differential level detector, αi, Q
119...Disconnector, (17a).

Claims (2)

[Claims] (1) Two current transformers installed in each line connected to the busbar
A gap transformer with a check winding that converts the secondary current into voltage at a predetermined ratio, a plurality of resistors for dividing the secondary voltage of the gap transformer, and a switch that selects the plurality of resistors to have a predetermined resistance ratio. an input device having a transformer that transforms the output of the switch, a rectifier circuit that full-wave rectifies the secondary output of the transformer, and a differential input device that is obtained by connecting all lines in series with the output of the switch. In a protective relay device comprising a ratio differential relay that receives as input an output and a suppression output obtained by connecting all lines of the output of the rectifier circuit in parallel,
a circuit for applying a predetermined simulated input to a test winding of the gap transformer with a test winding; a reference voltage generating circuit having a configuration equivalent to the gap transformer with a test winding, a plurality of resistors, and a switch; and the suppression output. a first detection element that detects the level of the differential output and a second detection element that detects the difference between the level of the differential output and the level of the reference voltage, the first detection element is in operation, and the second detection element is in non-operation. An inspection method characterized by determining whether the inspection is normal based on movement. (2) A disconnector that selects multiple busbars, a gapped transformer with inspection winding that receives the secondary current of the current transformer installed in each line connected to the busbar via this disconnector, A resistor, a switch, an auxiliary relay contact that opens and closes depending on the open/close state of the disconnector, a differential circuit in which the output of the switch is switched for each bus bar by the auxiliary relay contact, and this differential circuit. an input device connected to the input device and having a suppression circuit including a transformer and a rectifier circuit; and an input device for each bus receiving, as input, a differential output and a suppression output selected and derived for each bus from the input device. A protective relay device consisting of a differential relay with a ratio of An inspection method characterized in that an inspection judgment is made by connecting the results determined by the first and second detection elements with a logical sum.