JPS6346653B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a protective relay device for a phase shift transformer connected between a power system and a thyristor load.

Conventionally, there has been a device of this type as shown in FIG. The phase shift transformer 1 has windings Wa,
It has a winding 2 in which Wb and Wc are star-connected, and windings Wa ₁ , Wb ₁ and Wc ₁ are star-connected on the secondary side,
Furthermore, windings for phase shifting are added to these windings Wa ₁ , Wb ₁ , Wc ₁
It has a winding 3 in which Wb ₂ , Wc ₂ , and Wa ₂ are connected in series. One end of the windings Wa, Wb, Wc forming the midpoint O ₁ of the winding 2 is grounded, and their other ends are connected to the line 2 of the power system.
a, 2b, and 2c to which voltages V _A , V _B , and V _C are applied. The winding Wa ₁ forming the midpoint O ₂ of the winding 3,
One ends of Wb ₁ and Wc ₁ are grounded via a resistor 4.
The other ends of the windings Wb ₂ , Wc ₂ , Wa ₂ are wires 3a, 3b, 3
connected to the thyristor load via c. winding wire
Wa ₁ , Wb ₁ , Wc ₁ generate voltages V _A ′, V _B ′, V _C ′, and windings Wa ₂ , Wb ₂ , Wc ₂ generate −V _A ″, −V _B ″, −
By combining these, voltages Va, Vc, and Vb having a phase difference θ from the voltages V _A , V _B , and V _C are applied to the lines 3 a , 3 b _, and 3 c .

The currents in lines 3a, 3b, 3c are passed through current transformers 5a, 5
b, 5c to the phase shifter 6, and the phase difference θ
After receiving compensation corresponding to the current signals 6a, 6
b, 6c and are input to the protective relay 7. The protective relay 7 introduces the current of the wires 2a, 2b, 2c via current transformers 8a, 8b, 8c, and generates a current signal 6.
This is a normal differential protection relay that monitors the phase shift transformer 1 for abnormalities by comparing it with a, 6b, and 6c.

By the way, there are also phase shift transformers as shown in FIGS. 2 and 3. The phase-shifting transformer 9 has on the primary side a winding 2 identical to that of FIG. However, the winding 10 on the secondary side is the winding 3 shown in FIG.
In addition to the windings Wa ₁ , Wb ₁ , Wc ₁ and the windings Wc ₃ ,
Wa ₃ and Wb ₃ are connected in series. Winding Wc ₃ ,
Wa ₃ and Wb ₃ are voltages −V _C ″, − with phase difference −θ
V _A ″, −V _B ″ are also generated, and by combining with the voltages V _A ′, V _B ′, V _C ′ of the windings Wa ₁ , Wb ₁ , Wc ₁ , the wires 10a, which are connected to the thyristor load, 10b, 10c
Apply voltages Va′, Vb′, and Vc′ to

As shown in Figure 2, a polyphase phase shift transformer that generates voltages with phase differences θ and -θ can be protected by a three-phase input protective relay device as shown in Figure 1. It is clear that it cannot be done.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and provides a protection joint that can be protected with a simple configuration even if the phase shift transformer to be protected is a polyphase type. The purpose is to provide electrical equipment.

An embodiment of the present invention will be described below with reference to the drawings. First, the phase shift transformer 1 to be protected shown in FIG.
The winding configuration of No. 1 will be explained. The phase shift transformer 11 is 1
Winding 2 consisting of windings Wa, Wb, Wc on the next side and windings Wa ₁ , Wa ₂ , Wa ₃ , Wb ₁ , Wb ₂ , Wb ₃ , on the secondary side
It has a winding 12 consisting of Wc ₁ , Wc ₂ , and Wc ₃ .
The winding Wa ₁ has one end connected to the wire 13a, and the other end connected to the wire 3a via the winding Wb ₂ and to the wire 10a via the winding Wc ₃ . Winding Wb ₁ has one end connected to wire 1
3b, and connect the other end to wire 3b through winding Wc ₂ ,
And it is connected to the wire 10b via the winding Wa ₃ . The winding Wc ₁ has one end connected to the wire 13c, and the other end connected to the wire 3c via the winding Wa ₂ and to the wire 10c via the winding Wb ₃ .

As shown in Figure 4, the currents flowing through the windings Wa, Wb, Wc are Ia, Ib, Ic, the windings Wa ₁ , Wa ₂ , Wa ₃ ,
The current flowing through Wb ₁ , Wb ₂ , Wb ₃ , Wc ₁ , Wc ₂ , Wc ₃ is Iu ₁ + Iu ₂ , Iw ₁ , Iv ₂ , Iv ₁ + Iv ₂ , Iu ₁ , Iw ₂ ,
Iw ₁ + Iw ₂ , Iv ₁ , Iu ₂ and the number of turns is m,
If P, P, m, P, P, m, P, P and their current directions are determined as shown, Ia=m(Iu ₁ +Iu ₂ )−P(Iv ₂ +Iw ₁ )...( 1) Ib=m( _Iv1 + _Iv2 )-P( _Iw2 + _Iu1 )...(2) Ic=m( _Iw1 + _Iw2 )-P( _Iu2 + _Iv1 )...(3).

FIG. 5 is a connection diagram showing the configuration of a protective relay device according to an embodiment of the present invention. As shown, lines 3a, 3b, 3c, 10a, 10b, 10c, 1
3a, 13b, 13c are current transformers 3a, 3b, 3
c, 10a, 10b, 10c (turning ratio 1:1/P), and 13a, 13b, 13c (turning ratio 1:1/m). The wire 14a is the b end of the current transformer 15a, the a end of the current transformer 15c, the a end of the current transformer 16b, and the current transformer 16.
It is connected to the b end of the current transformer 17a, the a end of the current transformer 17a, and the b end of the current transformer 17b, and their output currents are combined to lead to a current Iab of the following equation.

Iab=m( _Iv1 + _Iv2 )-P( _Iw2 + _Iu1 )-m( _Iu1 + _Iu2 )+P( _Iv2 + _Iw1 )...(4) Also, the wire 14b is the a end of the current transformer 15a, b end of current transformer 15b, b end of current transformer 16a, current transformer 16
It is connected to the a end of the current transformer 17b, the a end of the current transformer 17b, and the b end of the current transformer 17c, and their output currents are combined to lead to a current Ibc of the following equation.

Ibc=m( _Iw1 + _Iw2 )-P( _Iu2 + _Iv1 )-m( _Iv1 + _Iv2 )+P( _Iw2 + _Iu1 )...(5) Furthermore, the wire 14c is the a end of the current transformer 15b, A end of current transformer 16, b end of current transformer 16b, current transformer 17a
is connected to the b end of the current transformer 17c and the a end of the current transformer 17c, and their output currents are combined to derive a current Ica of the following equation.

Ica = m (Iu ₁ + Iu ₂ ) - P (Iv ₂ + Iw ₁ ) - m (Iw ₁ + Iw ₂ ) + P (Iu ₂ + Iv ₁ ) ... (6) On the other hand, current transformers 8a, 8b, 8c are connected to wire 2a ,2
The currents Ia, Ib, and Ic of b and 2c are transformed and their secondary sides are mutually Δ-connected to generate currents Ia−Ib, Ib−Ic, and Ic−Ia between each phase corresponding to the currents Iab, Ibc, and Icb. are led to lines 2ab, 2bc, and 2ca.

Protective relay 7 has current Ia in wires 2ab, 2bc, 2ca
-Ib, Ib-Ic, Ic-Ia and lines 14a, 14b, 1
4c are compared with the currents Iab, Ibc, and Ica, and if an abnormality is detected, an operation is performed to protect the phase shift transformer 11.

As described above, according to the present invention, even if the phase shift transformer is a multiphase type, the current on the secondary side is combined via the current transformer, and the current on the primary side is matched. Since it is possible to obtain a three-phase current of 3-phase current, there is an effect that the configuration for protecting the phase shift transformer can be simplified.

[Brief explanation of drawings]

Fig. 1 is a connection diagram of a conventional protective relay device, Figs. 2 and 3 are diagrams showing the winding configuration of a phase shift transformer, and Fig. 4 is a diagram showing the winding configuration of a phase shift transformer. FIG. 5, which is a diagram showing the winding configuration of a phase transformer, is a connection diagram of a protective relay device according to an embodiment of the present invention. 1, 9, 11...phase shift transformer, 5a, 5b, 5
c, 8a, 8b, 8c, 15a, 15b, 15
c, 16a, 16b, 16c, 17a, 17b,
17c...Current transformer, 7...Protective relay. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. In a protective relay device for a phase shift transformer that has a plurality of windings for phase shifting on the secondary side and synthesizes multiphase currents using the windings, each phase of the primary side of the phase shift transformer a plurality of current transformers that transform currents on the secondary side of the phase shift transformer at a predetermined ratio, and a plurality of second current transformers that transform currents on the secondary side of the phase shift transformer at a predetermined ratio; A first connection that combines the output currents to derive a current between each phase, and a primary side current that is derived by combining the output currents of the second current transformer and the first connection. A protective relay comprising a second connection for deriving a secondary side current, and a protective relay for comparing the primary side current and the secondary side current derived by the first and second connections. Device.