The low tariff applicability time is controlled by the supplier with respect to the daily power system load diagram.

Why do we use Ripple Control?

The electricity demand varies during the day. In order not to be necessary to increase the production capacities of substations and transmission line capacity due to several hours of the peak demand daily, an idea was conceived to reduce the electricity price in the load decrease period, thus motivating customers to shift the operation of electrical appliances into the period of low load of the power system. Therefore, duel-rate tariffs (high and low tariffs) were implemented, where the electricity price for small-scale customers is not stable during the day. 

In order that customers need not be concerned about the type of the electricity tariff currently used by them, our company connects and disconnects electrical thermal appliances along with switching tariffs based on the adjustment of electrical installations for the thermal water treatment, accumulation or direct heating in the building, meaning that the correctly interlocked electrical thermal appliances may be switched on only during the low tariff period.

The Ripple Control coverage

The ripple control coverage map within the competencies of Stredoslovenská energetika, a.s. (after clicking on the selected town, the respective ripple control transmission times are displayed in an Excel spreadsheet):

 towns covered by the ripple signal
 areas where ripple control transmitters are installed

Ripple Control of Appliances

A drop in the distribution grid load also occurs in certain hours of the day, therefore we also provide a portion of the low tariff during the day. Dependent on the season, day and weather type, the natural load decrease varies; therefore, it is impossible to provide the daily portion of the low tariff by means of a switching clock. For this reason, we have started to replace switching clocks with ripple control receivers.

The ripple control signal transmitters transmit commands to the distribution grid according to the instructions from our dispatch center for our ripple control receivers at the customers´ places. These receivers respond to the commands by switching the electrometer tariffs and controlling the interlocking of selected electrical thermal appliances.

Appliances dividing

Your ripple controlled appliances can be structured into the following groups: 

For customers with tariffs:

• D24  /6 groups/(hot-water boilers and accumulator stoves),
• D14  /1 group/,
• C17  /1 group/, (two-rate business tariff - very low consumption)
• C27  /4 groups/, (two-rate business tariff - low offtake)
• C37  /2 groups/, (two-rate business tariff - larger offtake)
• D13 (the so-called cottager´s tariff). 

For customers with tariffs (fully electrified supply points with direct heating):

• D37 /8 groups/,
• D38 - uncontrolled,
• D39,
• for customers with D25 tariff   (suitable for fully electrified supply points with accumulation heating) - they are divided into 3 groups,
• for customers with D26 tariff  (suitable for fully electrified supply points with hybrid heating) - there is 1 group.

Connection of Ripple Control Receivers

The method of the customer´s metering device location and connection must be discussed with the electricity supplier, while the customer must also be made acquainted with the conditions for assignment of the relevant tariff according to the Price List (high tariff, low tariff applicability period, interlocking of appliances, etc.)


On the electrometer switchgear, the following may only be installed:

• electrometer,
• main circuit-breaker,
• tariff switch or ripple control receiver,
• ripple control receiver circuit-breaker,
• control relay,
• neutral terminal board,
• and possibly, other accessories serving exclusively for metering purposes.

Interference and Cross-Talks

In the distribution grid, there are  various interference types, which may cause the ripple control receiver equipment to function incorrectly.

A number of interference sources are for example: 

• various immersion pumps,
• rectifiers,
• magnetic amplifiers,
• thyristor controls,
• welders,
• poor quality installation connections and other sources of higher harmonics.

The originator of the consequences of interference phenomena is responsible for their removal. In the event that the customer fails to follow the written command to remove any interference, the power distribution company is authorized to limit or disconnect the power supply according to the commercial conditions and terms of the power supply.

If you suspect any ripple control receiver breakdown

Check if the fault is not on your own appliance. Repairs to damaged hot-water boilers, accumulating stoves, direct heating elements, controlled thermostats and private parts of house installations (i.e. everything except for the electrometer and ripple control receiver, ancillary relay) are not provided by SSE. In such case it is advised that you contact a professional electric installation company. Of course, in case of outages in the whole house or block of flats, the ripple controlled appliances will not function.

If you suspect a ripple control receiver failure, please call the SSE a.s. Customer Call Centre (CCC), where the CCC operator will ask you for the following data:

• Customer identification: Name and surname - Exact address of the building or the flat; Supply point number or the variable symbol defined in the bottom right hand corner of the invoice, or the number of your electrometer.
• Report the fault.
• Agree on an exact date of fault removal with the CCC operator.

However, in certain cases after the consequent electricity switching,  there may be a situation, where ripple controlled appliances will not start operation immediately. In case that in the given moment the low tariff (LT) applies, the appliance should start operation at the latest within one minute after the power supply recovery. If after electricity switching the high tariff (HT) applies, you must wait for the following LT interval. Information on the LT and HT transmission times may be obtained directly at our Customer Call Centre.

The published times are only for informational purposes and in exceptional cases, they may be changed by SSE in order to provide for an effective electricity use. However, SSE will observe the daily low tariff according to the Price List.

Based on your fault report, an SSE employee will visit you. In your own interest, please provide the SSE employee with access to the building (flat, house) in order for him to perform the check or replace the ripple receiver. In case that you have any troubles with the ripple control receiver or you are convinced that we have not provided you with the correct number of low tariff hours per day, please, report any such case  to us, preferably to the Customer Call Center.

How does your Ripple Control work?

This example does not apply to the current diagram and the used data serve only illustrational purposes. In case that the transmission diagram has the transmission hours programmed according to the Ripple Control transmission schedule for the following hours:

• Mon - Fri 22:15 - 6:15
• Sat - Sun 2:15 - 9:15, 13:30 - 16:30 

Then based on such hours, it follows that you will have the low tariff in the following hours:

• Monday 0:00 - 6:15, 22:15 - 24:00
• Tuesday 0:00 - 6:15, 22:15 - 24:00
• Wednesday 0:00 - 6:15, 22:15 - 24:00
• Thursday 0:00 - 6:15, 22:15 - 24:00
• Friday 0:00 - 6:15, 22:15 - 24:00
• Saturday 2:15 - 9:15, 13:30 - 16:30
• Sunday 2:15 - 9:15, 13:30 - 16:30

Regarding the switch from Friday to Saturday, the receiver activates the low tariff at 22:15. At midnight, the receiver switches to "Saturday" times, i.e. to the high tariff. The low tariff applies between 2:15 and 9:15. Similarly, on Sunday evening, the receiver switches consumption to the high tariff at 16:30, which will last until the midnight. After the midnight, your receiver switches to the low tariff, which applies until 6:15.

Time schedules

Ripple control signal transmission time schedules for the following areas:

• For the area of Liptovský Mikuláš the ripple control  signal is transmitted (191 Hz) from the 400 / 110 kV Liptovská Mara substation. The ripple control signal range - Liptovský Mikuláš, Ružomberok, Dolný Kubín, Námestovo and Tvrdošín Districts. 
• For the area of Žilina the ripple control signal is transmitted (191 Hz) from the  400 / 110 kV Varín substation. The ripple control signal  range - of Žilina, Lietavská Lúčka up to Rajecké Teplice, district of Bytča, districts of Čadca and Kysucké Nové Mesto Districts. 
• For the area of Martin the ripple control  signal is transmitted (191 Hz) from the  400 / 110 kV Varín substation. The reach of HDO signal -  Martin and Turčianske Teplice Districts. 
• For the area of Banská Bystrica the ripple control  signal is transmitted (191 Hz) from the  220/110 kV Medzibrod substation. The reach of HDO signal - Banská Bystrica, Detva, Brezno and Zvolen  Districts. 
• For the area of Rimavská Sobota the ripple control  signal is transmitted (191 Hz) from the 220/110 kV Medzibrod substation.  (R. Sobota, Lučenec, Fiľakovo, Hnúšťa districts).
• For the area of Žarnovica the ripple control   signal is transmitted (216,6 Hz) from the 110 / 22 kV Žarnovica substation . The ripple control  signal range - surroundings of Žarnovica. 
• For the area of Rajec the ripple control signal is transmitted (191 Hz) from the 110 / 22 kV Rajec substation. The ripple control  signal range - from the town of Rajecké Teplice up to the village of Čičmany.