Shanghai Huabang Industrial Business Network - Synchronous grounding relay

[Synchronous grounding relay]ZBZ-1 type rotor two-point grounding protection device

2026-6-14 10:01:01

The ZBZ-1 rotor two-point grounding device is suitable for protecting the DC magnetic circuit (rotor circuit) two-point grounding of synchronous generators.
2. Structure and action principles
The principle wiring is shown in Figure 1, mainly composed of ZBZ-1 type grounding (electromagnetic instantaneous action) relay 5 (internal wiring shown in Figure 2), FY-1 type anti current coil 6 and FY-1/B inverter 7, etc. The other components in Figure 1 are configured during screen assembly to illustrate their working principle.
When a grounding fault occurs in the excitation circuit of the generator, it does not constitute a fault current circuit and does not immediately pose a threat to the operation of the generator. While taking countermeasures, it can still continue to operate. If a two-point grounding fault occurs, it is not the case, and some excitation coils may be short circuited, even causing a fire. Therefore, after a grounding occurs in the excitation circuit of the motor, two-point grounding protection should be immediately activated.
The protection device is constructed using the principle of DC bridge balance.
Connect voltage divider 1 to the lead wire of the generator excitation coil slip ring, and the device is located between the sliding contact of 1 and the ground. When the excitation coil generates a grounding point (set as D1), a four arm bridge is formed with the sliding contact of voltage divider 1 and the grounding point as the diagonal. According to the principle of bridge balance, the resistance relationship between the four arms is R1 · R4=R2 · R3. Therefore, when a grounding occurs in the excitation circuit (during the measurement of the insulation resistance of the excitation circuit to ground), the protection device should be immediately put into operation, that is, close S, disconnect connection piece 2, close button 3, adjust the sliding contact of voltage divider 1, change its resistance values on both sides, set R3 and R4, until millivolt meter 4 indicates zero, at which point the "bridge" is in a balanced state. There is no current in coil I of instantaneous relay 5. Then open button 3 and connect connector 2. Place the device in a ready state.
When there is another grounding point in the excitation circuit, set the grounding point to D2, and it becomes a two-point grounding fault. As shown in Figure 1, the excitation coil between D1 and D2 is short circuited, the impedance of one arm decreases, the "bridge" loses balance, and current flows through the relay and coil. If the current is greater than the operating current of relay 5, the protection device will activate and cut off the generator.

Due to the uneven air gap between the generator rotor and stator magnets, the magnetic flux in various parts of the excitation coil will fluctuate due to the rotation of the rotor, and pulsating AC potential will be induced in the excitation coil with the increase or decrease of the air gap. Therefore, after the protective device is put into operation, AC current will be generated in coil 1 of relay 5. If the current is greater than the operating current of relay 5, the protection device will malfunction. In order to reduce the impact of this AC current on the protection device, an anti current coil "6" is connected in series with the coil I of relay "5" on the diagonal of the "bridge", and a compensation current transformer "7" that changes to 1 is used. The primary winding of the current transformer is connected in series with the relay coil I, and the secondary winding is connected to coil II of "5". When the AC current passes through the diagonal of the "bridge", the magnetic flux generated by the secondary circuit of the transformer is opposite in direction and equal in value to the AC magnetic flux component generated in coil I, thus greatly reducing the sensitivity of the relay under AC current. Due to the small DC resistance of the primary winding of the anti current coil and compensating current transformer, the transformer cannot transmit DC current, and their impact on the DC current during faults is also minimal.
The internal wiring diagram of relay 5 is shown in Figure 2, and the external appearance and installation dimensions can be found in the HK-01 housing in the appendix of this manual,
The accessory anti current coil and inverter have no base or shell, and can be directly installed behind the screen board of the enemy detection relay. Their appearance and installation hole size are shown in Figure 3.

3. The technical data of ZBZ-1 rotor two-point grounding protection device is shown in Table 1

Model Name	Technical data	Qualitative classification intensity	structure
ZBZ-1 relay	Action current: DC70 ± mA, each coil Return coefficient: �� 0.5 Action time: 0.25s, at 1.2 times the action current Contact capacity: DC �� 250V, �� 0.5A, ��=0.5 ± 0.75,50W AC 250VA	50Hz 2kV 1min	adopt HK��01a HK��01b
FY-1/K anti current coil	DC resistance: 8.5 �� Impedance: 5k ��, when f=50Hz and 1=0.04A
FY-1/B inverter	Transformation ratio: 1 Error: ± 3%, when the current does not exceed 0.2A

[Synchronous grounding relay]JT(DT) Synchronization check relay

2026-6-13 19:58:34

JT (DT) synchronous inspection relay

[Synchronous grounding relay]LD-3 type rotor one point grounding relay

2026-6-13 19:19:59

The LD-3 type rotor one point grounding relay (hereinafter referred to as the relay) is used to monitor the insulation of the excitation circuit of large generator rotors to ground. When a grounding fault occurs in the rotor of the generator or when the insulation drops to a certain value, the relay immediately acts, issuing a fault signal or directly tripping.

structure
The relay adopts an embedded rear wiring (JK-31K) structure.

Technical requirements for LD-3 rotor one point grounding relay

1. AC rated value 50Hz, 100V or 220V
2 action resistors
2.1 Setting range
0.5��1��2��5��10��15��20k��.
2.2 Setting error
The average of ten measurements is compared with the set value, and the error does not exceed ± 10%.
2.3 Return coefficient
Not greater than 2.
When the action time is 0.8 times the action resistance, it should not exceed 0.2 seconds.
4. Influence of capacitance
After connecting a parallel capacitor of 2 �� F to the subject's resistance, the change in action resistance compared to when there is no capacitor does not exceed ± 10%.
5. Impact of AC power supply
5.1 Voltage Influence: At 90% to 110% of the rated voltage, the change in operating resistance should not exceed 10% compared to the rated voltage.
5.2 Frequency Influence: The change in operating resistance between 47Hz and 53Hz should not exceed ± 10% compared to 50Hz.
6 Temperature effects
When the ambient temperature changes within the range of -5 �� to+45 ��, the average of ten measurements of the relay's operating value shall not differ by more than 10% compared to the average of ten measurements of the operating value under the reference conditions (20 ��± 2 ��).
7-contact disconnect capacity
When the voltage does not exceed 220V and the current does not exceed 0.2A, the breaking capacity of the relay contacts is:
a. In a DC inductive load circuit (��=5ms ± 0.75ms), it is 20W;
b. In the AC circuit (cos ��=0.4), it is 30VA.
8 Power consumption
The AC power supply consumes no more than 18VA at 50Hz and 220V.
The weight of the relay should not exceed 10kg.

Ordering Instructions
When placing an order, please specify:
a. Product model and specifications, shell structure form;
b. Name, code, and quantity of required spare parts;
c. Order quantity and delivery address.

��. Installation size:

��. Wiring diagram:

LD-3 type rotor one point grounding relay

[Synchronous grounding relay]ZD-6 type synchronous grounding relay

2026-6-13 19:19:50

Product Overview:
ZD-6 synchronous grounding relay is used for two-point grounding protection of synchronous generator DC excitation (rotor coil) circuit. Principle of DC four arm bridge.

Product Parameters:

ZD-6 synchronous grounding relay

[Synchronous grounding relay]BT-2 type synchronous inspection relay

2026-6-13 18:40:44

BT-2 synchronous inspection relay

[Synchronous grounding relay]DCH-1A type synchronous inspection relay

2026-6-13 18:35:29

1 Purpose
The DCH-1A type primary reclosing device (hereinafter referred to as the device) is used as a main component in the wiring of three-phase primary reclosing on transmission lines.

Meaning of Model 2

3 Principles and Structure
3.1 The device consists of a DS-32C type time relay (as a time element), a DZK-226 type fast intermediate relay (as an intermediate element), and several resistor and capacitor elements.
3.2 The device adopts an embedded plug-in structure, and the same core can be used for general embedded A32K, as shown in Figure 2. The relay is directly installed on the metal base plate in the plug-in, and the resistor and capacitor are first fixed on the insulation mounting plate, and then the mounting plate is fixed on the metal base plate in the plug-in. The plugin is installed inside a metal casing with a transparent plastic cover. Adopting an embedded plug-in structure is not only aesthetically pleasing, but also beneficial for users to adjust and maintain.
3.3 Terminal diagram and internal wiring diagram of the device, as shown in Figure 1.

Figure 1 Internal wiring diagram of DCH-1A primary reclosing device (back view)

Figure 2: Outline and Installation Dimensions of DCH-1A Type Primary Recloser Device

4 Main technical data
4.1 Rated voltage: DC 110V, 220V.
4.2 Rated current (holding current of intermediate component ZJ): 0.25A, 0.5A, lA, 2.5A.
4.3 The insulation strength of the relay should withstand a withstand voltage test of AC 50Hz, 2kY for 1 minute without breakdown or flashover.

5 Ordering Instructions
5.1 Model and name of the device.
5.2 Rated voltage and rated current.
5.3 Quantity of devices.

[Synchronous grounding relay]DD-1 type grounding relay

2026-6-13 18:35:20

1 Purpose
1.1 DD-1 type grounding relay (hereinafter referred to as relay) is an instantaneous overcurrent relay used for zero sequence overcurrent protection of high-voltage three-phase AC generators and motors in small grounding current power systems.
1.2 Relay coil connected to zero sequence current transformer (cable type, busbar type) or zero sequence current protection composed of three phase current transformers.
When the zero point of the protected motor is grounded through impedance, the relay is connected to the differential circuit of the inverter.
When the relay is connected to a zero sequence current filter composed of three phase current transformers, a blocking relay should also be connected to prevent misoperation caused by unstable currents due to external transient short circuits.

2 Structure and principle
2.1 Relays are instantaneous actions constructed according to electromagnetic principles. The electromagnetic system has two coils, and when the coils pass through current, they form a magnetic flux of electromagnetic torque in the magnetic conductor.
2.2 As relays are used for grounding protection in small grounding current systems, high sensitivity is required. Therefore, in addition to using a spring with a small reaction torque, compensation windings are added to both coils. After they are connected in series, they form a closed loop through a capacitor (C=0.47 �� f) to compensate for the reactance of the magnetizing coil, reducing the power required to generate the same magnetic flux in the magnetic conductor, improving the sensitivity of the relay, and reducing losses.
2.3 The outgoing line of the relay coil is connected to the terminal of the relay base, and a connecting piece is installed to change the coil from series to parallel, thus doubling the setting value of the relay.
The adjustment of the setting current of the 2.4 relay can be achieved by rotating the pointer on the dial to change the reaction torque of the balance spring. The relay has a dynamic contact.
The internal wiring of the 2.5 relay is shown in Figure 1.
2.6 Relays must be installed vertically on the screen board and can be wired in front or behind the board.
2.7 Relays have three structures: A11K, A11H, and A1lQ,Appendix II.

Figure 1 Internal wiring diagram of DD-1 grounding relay (back view)

Technical data of DD-1 grounding relay

The setting range of relay operating current and coil impedance value are shown in Table 1.

model	Setting range ��mA��	Coil series connection		Parallel connection of coils
model	Setting range ��mA��	Action current (mA)	Impedance (��)	Action current (mA)	Impedance (��)
DD-1��40	10~40	10~20	one hundred	20~40	twenty-five
DD��1��50	12.5��50	12.5��25	eighty	25~50	twenty
DD��1��60	15~60	15~30	sixty	30~60	fifteen

3.2 When relays of various specifications are connected in series or parallel with the coil, their impedance angle is+35 °.
3.3 Rated current 100mA, frequency 50Hz.
The accuracy of the scale on any set point shall not exceed ± 6%.
3.5 The variation in motion during five measurements at the same set point shall not exceed 6%
3.6 The return coefficient shall not be less than 0.5.
At the minimum setting current, the power consumption of the relay shall not exceed 0.015VA.
3.8 When the setting current is 1.2 times, the action time shall not exceed 0.3 seconds, and when the setting current is 3 times, the action time shall not exceed 0.1 seconds.
When the voltage does not exceed 250V and the current does not exceed 0.5A, the breaking capacity of the relay contacts is 20W in a DC inductive load circuit (time constant of 5 × 10-3s) and 100VA in an AC circuit.
The dielectric strength between each circuit of the 3.10 relay and the metal shell can withstand AC 50Hz, voltage 2kV, and no breakdown or flashover phenomenon after a 1-minute test.
3.11 The weight of the relay shall not exceed 1kg.

4 Ordering Instructions
4.1 Relay name and model.
4.2 Maximum setting current of relay (mA).
4.3 Number of relays.

[Synchronous grounding relay]DT-1 type synchronous inspection relay

2026-6-13 18:35:12

1 Purpose
The DT-1 synchronous relay (hereinafter referred to as the relay) is used in automatic reclosing lines of power supply lines at both ends to check the presence of line voltage and the phase difference between voltage vectors on the line bus, substation busbar, and busbar.

2 Structural principles
2.1 The relay is an electromagnetic instantaneous action relay, consisting of two coil windings on each of the two poles in the electromagnetic system: one winding of one coil is connected in series with the winding of the other coil, and the internal connection of the relay is shown in Figure 1.
2.2 The relay should have a voltage vector geometric difference applied to terminals 2-4 and 8-6 to adjust the phase angle difference by rotating the pointer to change the reaction torque of the spring. The scale should be indicated on the label.
2.3 Relays have dynamic breaking and dynamic closing contacts.
2.4 Relays have three structures: A11K, A11H, and A1lQAppendix II

Figure 1 Internal wiring diagram of DT-1 synchronous inspection relay (back view)

3 Technical data
3.1 The rated voltage data of the relay is shown in Table 1.

Model of relay

Rated voltage (v)

Number of the outgoing terminal

DT-1��90

Coil 1

Coil 2

sixty

thirty

2-4

8-6

DT-1��120

Coil 1

Coil 2

sixty

2-4

8-6

DT-1��130

Coil 1

Coil 2

one hundred

thirty

2-4

8-6

DT-1��160

Coil 1

Coil 2

one hundred

sixty

2-4

8-6

DT-1��200

Coil l

Coil 2

one hundred

2-4

8-6

3.2 At rated voltage, the relay operates when the voltage vector difference is within the range of 20-40 °.
3.3 At rated voltage, the return coefficient calculated by the voltage angle difference of the relay shall not be less than 0.8.
3.4 At rated voltage, the power consumption of each winding of the relay should not exceed 3VA.
All conductive parts of the 3.5 relay should withstand a test of AC 2kV (effective value), 50Hz for 1 minute for the insulation and voltage resistance of the casing.
When the voltage is 250V and the current is 2A, the breaking power of the contacts in a circuit with inductive load (time constant of 5 × 10-3s) is 50W; in an AC circuit, the breaking power of the contacts is 250VA (COS=0.8).
The accuracy of the scale on any set point shall not exceed ± 7.5%.
3.8 The consistency of action values at the same set point shall not exceed 6%
The weight of the 3.9 relay is lkg.

Use and maintenance of DT-1 synchronous inspection relay
Before using the relay, it is necessary to remove the casing, pull out the movement, and check for any mechanical damage during transportation. For example, if the rotor touches the magnetic pole, whether the coils of the balance spring touch each other, and the gap and movement on the rotor shaft; Set the pointer of the relay to the minimum setting position, rotate the movable system and magnetic pole position in the direction of the working position, and then release it. Check whether the movable system returns to its original position until the stop, and then make necessary adjustments and settings.
When readjusting the relay, it must be ensured.
a) The working position (in any direction) should not exceed 5 degrees;
b) The axial movement of the movable system is between 0.150.3mm;
c) The air gap between the rotor and the magnetic pole, the position of the rotating rotor when the relay is in the working position, should not collide with the magnetic pole at any position;
d) When the pointer rotates from the minimum scale position to the maximum scale position, the coils of the balance spring must not touch each other;
When the relay is activated, the bridge type contact should slide on the center line of the static contact (± 1mm), and the total gap between the dynamic and static contacts should not be less than 2mm.
f) The gap between the static contact and the limiting plate of the relay during dynamic closing or breaking should be greater than 0.1mm.
4.3 When adjusting the action of the relay, the minimum setting value is mainly used to adjust the reaction torque on the balance spring of the relay. The maximum value is sufficient to change the air gap between the rotor and the magnetic pole, and the return is to adjust the pressure and overtravel of the static spring.
4.4 It is not advisable to clean the contacts with sandpaper or other rough materials. It is recommended to clean the contacts with a sharp blade or a clean fine grinding stone, and then wipe them clean with a clean and soft cloth to avoid contact between fingers and corroded cloth.
Lubricants should not be added to the shaft and bearings of the relay. 5 Ordering Instructions
5.1 Product model and name.
5.2 Order quantity.

[Synchronous grounding relay]DT-13Q type synchronous relay

2026-6-13 18:34:46

1 Purpose
The DT-13Q synchronous check relay is used in automatic reclosing lines of two end power supply lines to check the presence of voltage on the line and the phase difference between the voltage vectors on the line and the substation busbar.

2 Structure and principle
2.1 This relay adopts embedded installation, and its main body is a plug-in structure
2.2 The main body of this relay is the same as the DT-13 synchronous relay.
2.3 DT-13Q type relay is an electromagnetic instantaneous action relay. A coil consisting of two windings is installed on each pole of the magnetic system. One winding of a coil is connected in series with the winding of another coil.
2.4 The relay responds to the geometric difference in voltage vectors applied to terminals 2-4 and 8-6. Adjust the phase angle difference by rotating the pointer to change the reaction force of the spring. The scale is expressed in degrees.
The 2.5 relay has one dynamic contact and one dynamic contact.
The appearance and installation dimensions of the 2.6 relay are shown in Figure 2.

Figure 1 Internal wiring diagram

Figure 2 Appearance and installation dimensions of DT-13Q relay

Technical requirements for DT-13Q synchronous relay
3.1 The specifications for the rated voltage data of relays are shown in the table below.

relay model	Rated voltage (V)		Number of the outgoing terminal
DT-13Q��90	Coil 1 Coil 2	sixty thirty	2-4 8-6
DT-13Q��120	Coil 1 Coil 2	sixty sixty	2-4 8-6
DT-13Q��130	Coil 1 Coil 2	one hundred thirty	2-4 8-6
DT-13Q160	Coil 1 Coil 2	one hundred sixty	2-4 8-6
DT-13Q��200	Coil 1 Coil 2	one hundred one hundred	2-4 8-6
DT-13Q��254	Coil 1 Coil 2	one hundred and twenty-seven one hundred and twenty-seven	2-4 8-6

3.2 At rated voltage, the relay operates when the phase angle difference between voltage vectors is within the range of 20 ° to 40 °.
3.3 At rated voltage, the return coefficient of the relay calculated by angle shall not be less than 0.8,
3.4 At rated voltage, the power consumed by each winding of the relay shall not exceed 3.5VA.
The conductive part can withstand AC 50Hz and voltage 2kV for 1min for dielectric strength of non charged metals.
When the voltage is below 220V and the current is below 2A, the breaking power of the contacts in a DC circuit with inductive load (time constant T is 10-3S) is 50W, and the AC circuit is 250VA.
The weight of the 3.7 relay is 1.6kg.

4 Ordering Instructions
4.1 Name and model of relay
4.2 Rated voltage of relay.
4.3 Number of relays.

[Synchronous grounding relay]DT-13 type synchronous relay

2026-6-13 18:34:37

The DT-13 synchronous relay is used in the automatic reclosing circuit of the two end power supply line, and its function is to check the existence of voltage on the line and the phase difference between the voltage vectors on the line and the substation busbar.

Overview of Structure 2
This relay is an electromagnetic instantaneous action relay, with a coil consisting of two windings installed on each of the two poles of the magnetic system. One winding of a coil is connected in series with the winding of another coil.
The relay responds to the geometric difference in voltage vectors applied to terminals 2-4 and 8-6, and adjusts the phase angle difference by rotating the pointer to change the spring's reaction force. The scale is expressed in degrees, and the relay has one dynamic contact and one dynamic contact.
The DT-13 relay is installed on a vertical panel and can be wired in front of or behind the board.
The internal wiring diagram of the relay is shown in Figure 1.

Figure 1 Internal wiring diagram of OT.13 relay (back view)

Technical data of DT-13 synchronous relay
3.1 The specifications for the rated data of relays are listed in Table 1.

relay model

Rated voltage (V)

Number of the outgoing terminal

DT-13��90

Coil 1

Coil 2

sixty

thirty

2-4

8-6

DT-13��120

Coil 1

Coil 2

sixty

2-4

8-6

DT-13��130

Coil 1

Coil 2

one hundred

thirty

2-4

8-6

DT-13��160

Coil 1

Coil 2

one hundred

sixty

2-4

8-6

DT-13��200

Coil 1

Coil 2

one hundred

2-4

8-6

DT-13��254

Coil 1

Coil 2

one hundred and twenty-seven

2-4

8-6

3.2 At rated voltage, the relay operates when the phase angle difference between voltage vectors is within the range of 20 ° to 40 °.
3.3 At rated voltage, the return coefficient of the relay calculated by angle shall not be less than 0.8,
3.4 At rated voltage, the power consumed by each winding of the relay shall not exceed 3.5VA.
The conductive part can withstand AC 50Hz and voltage 2kV for 1min for dielectric strength of non charged metals.
When the voltage is below 220V and the current is below 2A, the breaking power of the contacts in a DC circuit with inductive load (time constant T is 10-3S) is 50W, and the AC circuit is 250VA.
The weight of the 3.7 relay is 1.1kg.
The appearance and opening size of the DT-13 relay are shown in Figure 2 and Figure 3.

Figure 2 Outline dimension diagram

Figure 3 Hole Size Diagram

4 Ordering Instructions
4.1 Name, model, and rated voltage of the relay.
4.2 Wiring method (front or back of board).

[Synchronous grounding relay]DD-11Q type grounding relay

2026-6-13 18:34:27

1 Purpose
1.1 DD-1lQ type grounding relay is an instantaneous overcurrent relay used for zero sequence overcurrent protection of three-phase AC generators and motors in small grounding current power systems.
When the zero point of the protected motor is grounded through impedance, the relay is connected to the differential circuit of the inverter.
When the relay is connected to a zero sequence current filter composed of three phase current transformers, a blocking relay should also be connected to prevent possible misoperation caused by unstable currents due to external transient short circuits.

Structure and Principle of DD-11Q Grounding Relay
2.1 The relay adopts embedded installation, and the main body is a plug-in structure.
2.2 The main body of this relay is the same as the DD-11 grounding relay.
2.3 Relays are constructed based on electromagnetic principles. The instantaneous action and electromagnetic system have two coils, and when current passes through them, a magnetic flux that forms electromagnetic torque is generated in the magnetic conductor.
2.4 As relays are used for grounding protection in small grounding systems, high sensitivity is required. Therefore, in addition to using a spring with a small reaction torque, compensation windings are added to both coils. After they are connected in series, they form a closed circuit through a capacitor (C=0.5 �� f) to compensate for the reactance of the magnetizing coil, reduce the power required to generate the same magnetic flux in the magnetic conductor, improve relay sensitivity, and reduce losses.
The output head of the 2.5 coil is connected to the terminal of the relay base, and a connecting piece is installed to allow the coil to be changed from series to parallel, thus doubling the setting value of the relay.
2.6 The adjustment of the set current is carried out by rotating the pointer on the dial to change the reaction torque of the balance spring, and the relay has a dynamic contact.
The internal wiring diagram of the 2.7 relay is shown in Figure 1.
The appearance and installation dimensions of the 2.8 relay are shown in Figure 2.

Figure 1

Figure 2 Appearance and installation dimensions of DD11Q grounding relay

3 Technical data
The setting range of relay operating current and coil impedance value are shown in the table below.

model	Setting range (mA)	Coil series connection		Parallel connection of coils
model	Setting range (mA)	Action current (mA)	Impedance (��)	Action current (mA)	Impedance (��)
DD��11Q��40	10~40	10~20	eighty	20~40	twenty
DD��11Q��50	12��5��50	12��5��50	fifty-two	25~50	thirteen
DD��1lQ��60	15~60	15~60	thirty-six	30~60	nine

3.2 When relays of various specifications are connected in series or parallel with the coil, their impedance angle is+35 °.
3.3 Rated current 100mA, frequency 50Hz.
The accuracy of the scale on any set point shall not exceed ± 6%.
Scale accuracy=(maximum (or minimum) action value among five actions - scale value)/scale value X100%
The variation in motion during five measurements at the same set point shall not exceed 6%.
Action value deterioration=(maximum action value - minimum action value)/average of five actions X 100%
3.6 The return coefficient shall not be less than 0.5.
At the minimum setting current, the power consumption of the relay shall not exceed 0.012VA.
3.8 When the setting current is 1.2 times, the action time shall not exceed 0.3s; when the setting current is 3 times, the action time shall not exceed 0.1s.
When the voltage does not exceed 250V and the current does not exceed 0.5A, the breaking capacity of the relay contacts is 20W in a DC inductive load circuit (time constant of 5 × 10-3S) and 100VA in an AC circuit.
3.10 The dielectric strength between each circuit of the relay and the metal shell can withstand an AC of 50Hz and a voltage of 2kV for 1 minute without breakdown or flashover.
3.11 The weight of the relay shall not exceed 2kg.

4 Ordering Instructions
4.1 Relay name and model.
4.2 Maximum setting current of relay (mA).
4.3 Number of relays.

[Synchronous grounding relay]DD-11 type grounding relay

2026-6-13 18:34:18

1 Purpose
The DD-11 grounding relay is an instantaneous overcurrent relay used for zero sequence overcurrent protection of three-phase AC generators and motors in small grounding current power systems.

Overview of Structure 2
A relay is an instantaneous action composed of electromagnetic principles. The electromagnetic system has two coils, and when current passes through them, a magnetic flux that forms electromagnetic torque is generated in the magnetic conductor.
Due to the requirement of high sensitivity for relays used as grounding protection in small grounding systems, compensation windings are added to both coils in addition to using hairspring with small reaction torque. After they are connected in series, they form a closed circuit through a capacitor (C=0.5uf) to compensate for the reactance of the magnetizing coil, reducing the power required to generate the same magnetic flux in the magnetic conductor, improving the sensitivity of the relay, and reducing losses.
The outlet of the coil is connected to the terminal of the relay base, and a connecting piece is installed to allow the coil to be changed from series to parallel, thus doubling the setting value of the relay.
The adjustment of the set current is carried out by rotating the pointer on the dial to change the reaction torque of the balance spring, and the relay has a dynamic contact.
Relays are installed on vertical panels and can be wired in front of or behind the board.
The internal wiring of the relay is shown in Figure 1:

Figure 1

Technical data of DD-11 grounding relay
3.1 The setting range of relay operating current and coil impedance values are shown in the following table:

model	Setting range (mA)	Coil series connection		Parallel connection of coils
model	Setting range (mA)	Action current mA	Impedance (��)	Action current mA	Impedance (��)
DD-11/40	10-40	10-20	eighty	20-40	twenty
DD-11/50	12.5-50	12.5-25	fifty-two	25-50	thirteen
DD-11/60	15-60	15-30	thirty-six	30-60	nine

3.2 When relays of various specifications are connected in series or parallel with the coil, their impedance angle is+35 °.
3.3 Rated current 100mA, rated rate 50Hz.
The accuracy of the scale on any set point shall not exceed ± 6%.
Scale accuracy=(maximum (or minimum) action value among five actions - scale value)/scale value X100%

The variation in motion during five measurements at the same set point shall not exceed 6%.

Action value deterioration=(maximum action value - minimum action value)/average of five actions X 100%

3.6 The near return coefficient shall not be less than 0.5.
At the minimum setting current, the power consumption of the relay shall not exceed 0.012VA.
3.8 When the setting current is 1.2 times, the action time shall not exceed 0.3s; when the setting current is 3 times, the action time shall not exceed 0.1s.
When the voltage does not exceed 250V and the current does not exceed 0.5A, the breaking capacity of the relay contacts is 20W in a DC inductive load circuit (time constant of 5 × 10-3s) and 100VA in an AC circuit.
3.10 The dielectric strength between each circuit of the relay and the non charged metal can withstand AC 50Hz, voltage 2kV, and undergo a 1-minute test without breakdown or flashover.
3.11 The weight of the relay shall not exceed 1.5k8.
The appearance and opening size of DD-11 relay are shown in Figure 2 and Figure 3.

Figure 2 Outline dimension diagram

Figure 3 Hole Size Diagram

4 Ordering Instructions
When placing an order, please specify:
4.1 Name and model of relay.
4.2 Maximum setting current (mA).
4.3 Wiring method (front board wiring or back board wiring); If not specified, supply according to the wiring at the back.

[Synchronous grounding relay]BT-1B type synchronous inspection relay

2026-6-13 18:33:25

Purpose:
The BT-1B synchronous check relay is used in the automatic reclosing circuit of the two terminal power supply system as a checking element for voltage and synchronization.

Working Principle:
2.1 The relay consists of voltage transformers YH1 and YH2, rectification and filtering circuits, triggers, and reed relays. Installed in a modular plug-in housing. The schematic diagram of the principle wiring is shown in Figure 2.
2.2 Two AC voltages (or currents) are respectively applied to the two primary windings of voltage transformers YH1 and YH2, and the secondary windings are connected to the rectifier bridge with opposite polarity. When two voltages (or currents) are in phase at once, due to the reverse polarity connection of the secondary winding, the potential generated on the voltage transformer cancels each other out, and the secondary output voltage is equal to zero (unbalanced voltage does not exceed 0.5V). The trigger is still in its original state (BG1 conduction, BG2 cutoff), and the reed relay does not operate. When two voltages (or currents) are in different phases at once, the potential generated on the voltage transformer cannot cancel each other out, while a potential is generated in the second phase. The magnitude of the secondary output voltage is related to the phase difference and amplitude of the two voltages (or currents) at once. When the amplitude is constant, the larger the phase difference, the larger the secondary output voltage, and vice versa. The vector diagram is shown in Figure 1.
2.3 After rectification and filtering, the secondary output voltage is applied to the trigger. When the signal voltage reaches the set value, the trigger flips (BG1 is turned off, BG2 is turned on), the reed relay acts, the dynamic breaking contact opens, and the dynamic closing contact closes.
When any input voltage (or current) is zero or very low, the situation is the same as when two voltages (or currents) are in different phases, and the relay should also immediately act.
The setting of the 2.5 relay action angle is achieved using potentiometer R8.
The BT-1B synchronous inspection relay is a protruding plug-in structure (T) type.

Main technical parameters:
3.1 According to the rated voltage or rated current, the specifications of the relay are shown in Table 1
3.2 DC rated voltage: 220V, 110V, 48V.
3.3 Rated frequency: 50Hz.
3.4 Contact form: dynamic connection, dynamic disconnection.
3.5 Action angle setting range: 20 ° to 40 °.
3.6 Return coefficient: not less than 0.85.
3.7 DC power supply variation: When operating at 220V and 110V, it is allowed to vary within the range of 80-110%; At 48V, it is allowed to vary within the range of 90-110%, and the relay should be able to work normally.
3.8 Power consumption: The relay AC circuit shall not exceed 1VA; the DC circuit shall not exceed 6W at 220V; the power consumption shall not exceed 4W at 110V; and the power consumption shall not exceed 2W at 48V.
3.9 Contact breaking capacity: In a DC inductive load circuit with a voltage not exceeding 220V and a current not exceeding 0.2A (time constant not exceeding 5ms ± 0.75), the breaking capacity is 25W, and in an AC circuit (coso=0.4 ± 0.1), it is 30VA.
3.10 Lifespan: 5000 cycles.
3.11 Weight: Approximately 1.05kg.

Wiring diagram behind the relay:
The installation wiring diagram is shown in Figure 3.

Relay external dimensions and opening dimensions:
The appearance and installation dimensions of the BT-1B synchronous inspection relay are shown in Figure 4 of the general structural system.

Ordering instructions:
4.1 Name and model of relay.
4.2 Rated values of relays.
4.3 Order quantity.
4.4 Delivery address.

[Synchronous grounding relay]BT-1B/R type synchronous inspection relay

2026-6-13 18:31:56

Purpose:
The BT-1B/R synchronous check relay is used in the automatic reclosing circuit of the two terminal power supply system as a checking element for voltage and synchronization.

Working Principle:
Principle of operation
The relay consists of voltage transformers YH1 and YH2, rectification and filtering circuits, triggers, and reed relays. The schematic block diagram is shown in Figure 1
Two alternating voltages (or currents) are applied to the two primary windings of voltage transformers YH1 and YH2, respectively, with their secondary windings connected to the rectifier bridge in opposite polarity. When two voltages (or currents) are in phase at once, due to the reverse polarity connection of the secondary winding, the potential generated on the voltage transformer cancels each other out, and the secondary output voltage is equal to zero (the unbalanced voltage does not exceed 0.5V). The trigger is still in its original state (BG1 conducts, BG2 is cut off), and the reed relay does not operate. When the two voltages (or currents) are in different phases, the potential generated on the voltage transformer cannot cancel each other out, and the potential is generated on the secondary winding. The magnitude of the secondary output voltage is related to the phase difference and amplitude of the two voltages (or currents) on the primary winding. When the amplitude is constant, the larger the phase difference, the larger the secondary output voltage, and vice versa. The vector diagram is shown in Figure 2.
The secondary output voltage is rectified and filtered before being applied to the trigger. When the signal voltage reaches the set value, the trigger flips (BG1 is turned off, BG2 is turned on) and the reed relay acts, opening the dynamic breaking contact and closing the dynamic closing contact.
When any input voltage (or current) is zero or very low, the situation is the same as when two voltages (or currents) are in different phases, and the relay should also immediately act.
The setting of the relay action angle is achieved using potentiometer R8.

Main technical parameters:
3.1 According to the rated AC voltage, the specifications of the relay are shown in the table below
3.2 DC rated voltage: 220V, 110V, 48V.
3.3 Rated frequency: 50Hz.
3.4 Contact form: dynamic connection, dynamic disconnection.
3.5 Action angle setting range: 20 ° to 40 °.
3.6 Return coefficient: not less than 0.85.
3.7 DC power supply variation: When operating at 220V and 110V, it is allowed to vary within the range of 80-110%; At 48V, it is allowed to vary within the range of 90-110%, and the relay should be able to work normally.
3.8 Power consumption: The relay AC circuit shall not exceed 1VA; the DC circuit shall not exceed 6W at 220V; the power consumption shall not exceed 4W at 110V, and the power consumption shall not exceed 2W at 48V.
3.9 Contact breaking capacity, for DC inductive load circuits with voltage not exceeding 220V and current not exceeding 0.2A (time constant not exceeding 5 × 10-3s), the breaking capacity is 25W and 30VA in AC circuits.
3.10 Electrical lifespan: 5 × 103 cycles.
3.11 Dielectric Strength Relay: Each conductive circuit of the relay should be able to withstand an AC test voltage of 2kV (effective value) and 50Hz between the exposed non charged metal parts and the casing, as well as between the input circuit and the contacts. After a 1-minute test, there should be no insulation breakdown or flashover phenomenon.
3.12 Working conditions
a) The usage location does not allow explosive media, and the surrounding media should not contain corrosive metals, gases that damage insulation, or conductive media. It is not allowed to be filled with water vapor or have serious mold presence;
b) Strong vibrations and impacts are not allowed in the usage location;
c) The usage location should have facilities to defend against rain, snow, wind, and sand;
d) The usage location does not allow an external magnetic induction intensity exceeding 1.5mT.
3.13 Electrical anti-interference relays shall comply with GB7261 and GB6261 "Electrical anti-interference tests for static relays and protective devices".

BT-1B/R synchronous inspection relay back wiring diagram:
The terminal diagram of the protruding modular insertion structure (BT-1B/R type) behind the relay is shown in Figure 3. There is a potentiometer on the panel, and R2 is used for setting the delta angle.

Relay external dimensions and opening dimensions:
Refer to Figures 4 and 8 in the protruding modular insertion structure.

Ordering instructions:
5.1 Product model, name, rated voltage, structural form, etc.
5.2 Order Quantity.
5.3 Relay matching: such as base, socket, etc. (must be ordered separately).